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VOLUME  111  NUMBER   1 

JANUARY,  1911 

CHICAGO,  IL  60616 



G.  H.  EMIN 



JANUARY,    1911 



Member  A.    I.   M.   E. 

The  conservation  of  our  fuel  resources,  which  has  become  a 
subject  of  active  interest  in  past  few  years,  is  exemplified  in 
the  history  of  the  briquetting  industry  as  we  follow  its  de- 
velopment in  Europe  and  later  in  this  country.  We  may  nat- 
urally expect  to  find  its  inception  in  the  countries  where  a 
thrifty  people  have  learned  to  husband  their  resources  and 
turned  to  good  account  their  poor  or  depleted  fuel  supply.  A 
country  like  ours,  of  such  wonderful  natural  resources  and  so 
profligate  in  their  use,  does  not  offer  the  proper  stimulus  to 
an  industry  which  depends  upon  trade  conditions  of  high  prices 
where  close  profits  have  forced  economy  in  the  small  detail 
of  saving. 


The  name  "briquet,"  which  is  now  universally  used  for 
all  forms  of  compressed  fuel,  was  applied  originally  in  Paris 
to  fuel  made  from  peat  with  the  addition  of  wet  clay,  similar 
to  our  present  day  methods  of  making  wet  clay  bricks.  The 
term  was  later  made  to  include  all  fuel  made  by  compression 
without  the  use  of  a  binder  in  contradistinction  to  that  made 
from  bituminous  and  anthracite  coal  with  pitch  or  other  bind- 
ers. We  find  numerous  other  names  used,  such  as  "boulet, " 
"charbon  agglomeres,"  or  "houilles  agglomeres,"  abbreviated 
to  "agglomeres"  in  France;  "briquettes  de  charbon"  in  Bel- 
gium; "patent  fuel"  and  "compressed  fuel"  in  England; 
"kohlensteine"  or  "kohlenzeiglen"  in  Germany,  applied  gen- 
erally to  briquets  made  from  true  coals  with  binder:  while 
"artificial  fuel"  embraced  all  fuel  manufactured  from  coal, 
lignite,  peat  or  other  form  of  combustible. 

In  America  the  word  "briquet"  has  been  accepted  as  a 
generic  term  for  the  product,  while  specific  names  such  as 
"pressed  fuel,"  "coalette"  and  "carbonet"  are  found  in  the 
trade.    "Eggettes"  are  generally  applied  to  briquets  made  on 

*Class  of  1897.     Briquetting  Engineer,  Roberts  &  Schaefer  Co.,   Chicago. 


[Jan.,  1911 

the  so-called  "Belgian  roll"  type  of  press,   a  name  said  to 
have  been  invented  by  Mr.  Ware  B.  Gay  for  the  product  of  a 
Loiseau  press  of  this  type.    Fig.  1  shows  samples  of  American 
made  briquets. 

The  earliest  record  on  the  briquetting  of  coal  was  suggested 
in  a  pamphlet  by  Sir  Hugh  Pratt  in  1594.  The  first  satisfactory 
briquetting  machine  was  built  in  France  in  1842  by  M.  Marsais, 
and  since  that  time,  the  industry  has  gone  steadily  forward  in 
all  the  European  countries. 



A.  Briquet   made   by   U.   G.   I.    Co.,   Philadelphia. 

B.  Briquet    made    on    Zwoyer    press. 

C.  "Eggette"   made   by    Solvay    Process  Co.,  Detroit. 

D.  "Carbonet"    made   at    Hartshorne,    Okla.,    plant. 

E.  Briquet    made    on    Johnson    press. 

F.  Briquet   made    by   Briquette    Coal    Company. 

The  first  briquetting  plants  were  installed  in  England  in 
1846,  Belgium  in  1852  and  Germany  in  1861.  About  1870,  the 
briquetting  of  brown  coals  was  first  successfully  accomplished 
in  the  last  named  country. 

Prominence  was  given  to  the  industry  by  the  exhibits  of 
briquetting  machinery  at  the  Paris  Exhibition  of  1867, 
and  the  following  year  we  find  the  first  recorded  in- 
terest for  coal  briquetting  in  America.  In  1870  E. 
F.  Loiseau  installed  at  Port  Richmond,  Philadelphia,  the  first 
coal  briquetting  plant.  The  press  used  was  of  Belgian  type 
known  as  the  "Loiseau  rolls"  and  made  eggettes  weighing 
about  eight  ounces,  using  92%  anthracite  culm  and  8%  clay 

Vol.  Ill,  No.  1]      BRIQUETTED  COAL:  MALCOLMSON 

as  a  bond.  These  briquets  were  water-proofed  with  a  varnish 
of  shellac  and  benzine,  but  the  cost  was  prohibitive.  The  plant 
was  never  a  success,  either  mechanically  or  commercially,  and 
was  finally  abandoned,  but  it  marks  the  first  step  of  the  bri- 
quetting industry  in  this  country  and  had  its  influence  on  the 
future,  not  without,  we  believe,  beneficial  results. 

The  Delaware  and  Hudson  Canal  Company  built  a  similar 
plant  at  Rondout,  in  1876,  which  was  later  absorbed  by  the 
Anthracite  Fuel  Company  in  1878  and  operated  until  1880.  This 
plant  also  briquetted  anthracite  screenings  using  pitch  made 
from  gas  house  tar  as  a  binder.  The  third  plant  in  the  east 
to  use  the  Loiseau  roll  press  was  built  at  Mauch  Chunk,  Penn- 
sylvania, and  was  short  lived.  The  binder  in  these  briquets 
made  a  smoky  fuel  which  disintegrated  in  the  fire  and  was 
otherwise  unsatisfactory. 

The  next  important  plant  established  in  the  United  States 
was  at  Mahanoy  City,  Pennsylvania,  in  1890,  by  the  Anthra- 
cite Pressed  Fuel  Company.  The  plant  was  designed  by  the 
Uskside  Engineering  Company  of  Newport,  England,  using  a 
Stevens  press.  The  briquets  were  rectilinear  with  an  eagle  on 
one  side  and  the  word  "Reading"  on  the  other  and  weighed 
eighteen  pounds.  The  plant  had  a  capacity  of  400  tons  per  day 
of  ten  hours.  The  dies  were  changed  later  to  make  two-pound 
briquets  and  the  capacity  reduced  to  300  tons.  The  binder  was 
pitch  made  from  coke  oven  tar  imported  from  England  and 
8%  was  used  in  making  the  briquets.  The  Philadelphia  and 
Reading  Railroad  expected  to  save  $50,000.00  a  year  in  their 
fuel  by  means  of  this  plant,  but  the  briquets  were  not  satis- 
factory owing  to  the  high  ash  content  of  the  culm  and  the  ex- 
cessive cost  of  binder.  The  plant  failed  in  1892  owing  to  a 
slump  in  the  price  of  coal  and  inability  to  get  sufficient  quan- 
tities of  binder,  but  it  is  noteworthy  as  marking  the  first  im- 
portant attempt  to  make  briquets  for  railroad  purposes. 

In  1892  Mr.  Ware  B.  Gay  built  a  plant  at  Gayton,  near  Rich- 
mond, using  one  set  of  Loiseau  rolls  for  the  briquetting  of 
Virginia  semi-anthracite  slack  and  using  coal  tar  pitch  as  a 
binder.  The  capacity  of  this  plant  was  doubled  later.  Similar 
plants  were  installed  at  this  time  at  Milwaukee  and  Chicago 
for  briquetting  anthracite  dust  and  bituminous  slack  made 
at  transfer  plants  in  these  cities.  In  the  dull  coal  season  the 
Chicago  plant  made  briquets  of  iron  ore  dust  for  the  Illinois 
Steel  Company. 

A  more  pretentious  plant  was  built  in  the  same  year  at 
Huntington.  Arkansas,  under  patents  of  M.  Nirdlinger.  con- 
trolled by  the  National  Eggette  Coal  Company  of  New  Jersey. 

THE    ARMOUR    ENGINEER  [Jan.,  1911 

The  Huntington  plant  made  briquets  of  a  mixture  of  Arkansas 
semi-anthracite  and  bituminous  coals,  using  hard  pitch  and  coal 
tar  as  a  binder.  These  plants  failed  generally  because  of  in- 
experience in  preparing  the  coal  which,  as  a  rule,  was  too 
dirty;  inability  to  get  uniform  pitch  of  the  proper  specifica- 
tions ;  the  expense  of  briquetting ;  and  the  cheapness  of  the  coal 
with  which  the  briquets  must  compete.  These  observations 
were  made  by  Mr.  Gay  in  referring  to  the  Eichmond  plant,  to 
which  he  added  that  "prismatic  shape  is  less  desirable  than 
one  affording  better  combustion  by  forming  interstices  between 
the  pieces,  especially  when  used  for  domestic  purposes." 
Recent  American   Plants. 

We  find  the  next  development  of  the  briquetting  industry 
in  California,  where  more  actual  progress  has  been  made  than 
in  any  other  locality,  although  at  the  present  time  no  plants 
are  operating.  The  first  plant  was  built  at  Stockton,  California, 
to  make  briquets  from  lignite  mined  at  Tesla.  Bituminous 
screenings  were  mixed  with  the  lignite  and  asphaltum  residuum 
from  the  distillation  of  California  petroleum  used  as  a  binder. 
The  press  was  designed  by  Mr.  Robert  Schorr  of  San  Fran- 
cisco, and  combined  the  continuous  operation  of  the  rotary 
type  with  the  exactness  and  efficiency  of  the  plunger  press. 
Two  presses  were  installed  having  a  capacity  of  125  tons  per 
day  of  "boulets"  weighing  from  6  to  8  ounces.  The  Mammoth 
Oil  Refining  Company,  a  subsidiary  enterprise,  spent  consider- 
able money  in  developing  a  distillation  plant  for  making 
briquetting  pitch.  The  plant  burned  in  1005.  These  briquets 
were  used  on  the  San  Francisco  and  San  Joaquin  Railway 
and  made  a  satisfactory  locomotive  fuel,  eliminating  the  ob- 
jectionable features  of  raw  lignite. 

Another  Schorr  press  was  installed  at  Oakland,  California, 
by  the  "Western  Fuel  Company  for  briquetting  the  accumula- 
tions of  slack  coal  on  its  docks.  The  operations  of  this  plant 
were  discontinued  at  the  time  of  the  earthquake  when  the  price 
of  pitch  became  prohibitive. 

A  briquet  press  of  novel  design  was  built  by  Mr.  C.  R.  Allen 
and  installed  at  Pittsburg,  Calif.,  for  the  briquetting  of  lignite 
mined  at  Somersville.  This  press  was  on  the  order  of  the  roll 
type,  making  a  cylindrical  briquet  weighing  8  to  10  ounces. 
The  plant  had  a  capacity  of  5  tons  per  hour  using  asphaltic 
pitch  as  a  binder. 

The  Standard  Coal  Briquetting  Company  of  Oakland  and 
the  American  Briquetting  Company  of  San  Francisco  made  un- 
successful  attempts   to   produce    commercial    briquets,    which 


failed  on  account  of  economic  conditions  already  mentioned. 
The  latter  plant  experimented  with  Coos  Bay  lignite  mixed 
with  coal  yard  screenings. 

The  Arizona  Copper  Company,  Clifton,  Arizona,  is  making 
briquets  for  its  own  use,  from  the  slack  of  sub-bituminous  coal 
mined  at  Gallup,  N.  M.  A  Yeadon  press  built  in  England  is 
used,  making  four-pound  briquets  of  prismatic  shape  at  the 
rate  of  about  2%  tons  per  hour.  Asphaltic  pitch  is  used  as 
a  binder.  The  economic  value  is  found  in  the  storing  qualities 
of  the  fuel  made  from  a  slack  that  will  either  "fire"  or  at  least 
deteriorate  rapidly  when  stored.  Coke  breeze,  hitherto  wasted, 
has  also  been  mixed  with  the  slack  coal. 

The  Washington  Coal  Briquetting  Company  of  Seattle  has 
built  a  plant  using  a  plunger  type  press  designed  by  Mr.  Henry 
Mould  of  Pittsburg,  constructed  along  the  lines  of  his  press  for 
briquetting  flue  dust  and  ores.  This  plant  was  completed  in 
1908,  but  up  to  date  has  not  made  a  commercial  product.  It 
was  designed  to  utilize  the  slack  from  low-grade  fuels  sold  for 
domestic  purposes  in  Seattle.  A  press  of  the  Couffinhal  type, 
built  by  the  Coal  Briquette  Machine  Company  of  Oshkosh, 
Wis.,  has  been  installed  at  Sheboygan  to  briquet  anthracite 
dust  from  the  coal  yards.  This  plant,  installed  in  1907,  has  not 
yet  been  put  in  commercial  operation.  The  briquets  are  cylin- 
drical and  weigh  about  12  ounces.  The  press  has  a  capacity  of  4 
tons  per  hour. 

The  National  Pressed  Fuel  Company  has  installed  a  press 
and  plant  designed  by  George  W.  Ladley  and  sold  a  limited 
amount  of  briquets  in  Indianapolis  last  winter  to  domestic 
trade.  The  press  is  an  adaptation  of  the  Brogneaux  rotary 
type,  and  belongs  to  the  same  class  as  the  Schorr  press,  com- 
bining the  rotary  and  reciprocating  types.  It  has  a  capacity 
of  12  tons  per  hour  of  6-ounce  briquets,  cylindrical  in  shape, 
made  from  southern  Indiana  screenings  and  hard  coal  tar  pitch. 
About  8%  of  binder  is  used. 

The  National  Fuel  Briquette  Machinery  Company  has  a 
small  plant  at  the  foot  of  Court  St.,  Brooklyn,  for  demonstrating 
the  Devillers  press.  The  press  is  of  the  Belgian  rolls  type,  has  a 
capacity  of  5  tons  per  hour,  and  makes  an  eggette  weighing 
about  2  ounces  out  of  small-sized  anthracite  and  coal  tar  pitch, 
imported  from  Europe.  The  briquets  are  sold  for  domestic 
purposes.  One  of  these  presses  was  purchased  a  few  years 
ago  by  the  Consolidated  Gas  Company  of  New  York  to  make 
briquets  from  coke  breeze,  but  the  product  has  not  yet  been 

The  Zwoyer  Fuel  Company  of  New  York  is  one    of   the 

THE    ARMOUR    ENGINEER  [Jan.,  1911 

pioneers  of  briquetting  in  this  country  and  has  developed  an 
efficient  press  of  the  Loiseau  type  having  a  maximum  capacity 
of  15  tons  per  hour  of  2-ounce  briquets.  The  briquets  are 
pillow  shaped,  that  is,  rectangular  in  plan,  but  ovoid  in  both 
cross  sections.  This  shape  is  a  development  on  the  one  advo- 
cated by  Hutteman  and  Spiecker  and  is  designed  to  economize 
the  effective  area  of  the  rolls  and  reduce  the  amount  of  waste 
in  briquetting.  Several  plants  have  been  built  by  this  company 
in  and  about  New  York,  in  the  past  ten  years,  marking  the 
perfection  of  their  press  and  other  equipment.  At  the  present 
time  the  only  operating  plant  is  at  Perth  Amboy,  owned  by 
the  New  Jersey  Briquetting  Company.  The  product  is  loaded 
mechanically  in  barges  direct  from  the  storage  bins  at  the 
plant,  and  sold  in  New  York  and  Brooklyn  in  competition  with 
stove  sizes  of  anthracite.  The  briquets  are  made  from  anthra- 
cite screenings  with  10%  of  hard  coal  tar  pitch  as  a  binder. 
The  most  important  plant  using  the  Zwoyer  press  and  process 
is  at  Bankhead,  Alberta,  Canada,  at  the  breaker  of  the  Bank- 
head  Mines,  Ltd.  This  plant  has  been  operating  since  1906 
and  has  recently  doubled  its  capacity,  making  during  March, 
1 909,  over  15,000  tons  of  briquets.  The  coal  used  is  a  friable 
semi-anthracite,  and  about  10%  of  coal  tar  pitch  is  used  as  a 
binder.  The  output  is  sold  principally  for  domestic  purposes 
and  shipped  as  far  east  as  Winnipeg. 

A  press  of  similar  design  is  manufactured  by  the  Mashek 
Engineering  Company  of  New  York.  One  of  these  presses  is 
installed  at  a  plant  of  the  D.  Grieme  Coal  Company,  West  27th 
Street,  New  York,  making  briquets  of  anthracite  buckwheat 
and  coal  tar  pitch  binder. 

The  United  Gas  Improvement  Company  of  Philadelphia 
and  the  Solvay  Process  Company  of  Detroit  have  done  con- 
siderable work  in  developing  the  briquet  industry,  as  a  means 
of  disposing  of  their  by-products  and  not  primarily  to  market 
briquets.  The  United  Gas  Improvement  Company  purchased 
and  installed  in  1905  a  rotary  press  manufactured  by  the 
Societe  Nouvelle  des  Etablissements  de  L'Horme  et  de  La 
Buire,  Lyon,  France,  and  are  making  an  eggette  weighing  5 
ounces.  As  the  plant  now  stands  they  have  the  original  press 
and  one  of  this  type  adapted  to  American  conditions,  making 
a  pillow-shaped  briquet  weighing  2  ounces.  The  presses  have 
a  capacity  of  5  tons  per  hour.  Anthracite  buckwheat  and 
smaller  sizes  are  made  with  10%  water  gas  pitch  into  briquets 
used  exclusively  for  making  water  gas,  and  giving  better  re- 
sults than  the  larger  sizes  of  anthracite. 

The  Solvay  plant  has  passed  through  a  longer  experimental 

Vol.  Ill,  No.  1]     BRIQUETTED  COAL:  MALCOLMSON 

period  beginning  in  1904  with  the  installation  of  a  Johnson 
press  similar  to  that  used  at  the  St.  Louis  plant  of  the  govern- 
ment. This  press  originally  made  8-pound  prismatic  briquets; 
the  dies  were  changed  to  make  briquets  weighing  4  ounces,  but 
the  troubles  incident  to  feeding  the  dies  and  the  reduced  out- 
put led  the  company  to  abandon  that  press  and  substitute  one 
built  by  Mr.  Mashek,  which  did  not  prove  satisfactory.  The 
company  has  recently  installed  a  press  similar  to  the  one  at 
Point  Breeze,  made  under  the  U.  G.  I.  specifications,  but  mak- 
ing 2-ounee  eggettes.  These  briquets  contain  coke  breeze, 
Pocahontas  slack  and  8%  hard  pitch  made  from  coke  oven 

Fig.    2.      Johnson    press   at    Government    Coal    Testing   Plant, 
St.    Louis,   Mo. 

tar,  and  the  company  is  now  experimenting  with  a  process 
to  eliminate  the  smoke  by  partially  coking  the  briquets. 

The  Briquette  Coal  Company  had  an  experimental  plant 
on  Staten  Island.  A  Couffinhal  type  of  press,  built  by  Schuch- 
termann  &  Kremer,  Dortmund,  Germany,  making  4  tons  per 
hour  of  1%-pound  rectilinear  briquettes,  was  installed  together 
with  a  Belgian  press  made  by  H.  Stevens  of  Charleroi,  making 
5-ounce  eggettes  at  about  7  tons  per  hour.  The  plant  was 
never  designed  to  operate  commercially  and  has  recently  been 
abandoned.  The  equipment  is  being  installed  in  a  plant  near 
the  mines  at  Murphysboro,  DL,  to  make  briquets  under  con- 

10  THE    ARMOUR    ENGINEER  [Jan.,  1911 

tract  with  the  St.  Louis  and  Big  Muddy  Coal  &  Iron  Company. 

The  work  of  the  United  States  Geological  Survey  at  St. 
Louis  is  fully  described  in  government  bulletins  and  need  only 
be  mentioned  here.  During  the  exposition  period  a  Johnson 
press  made  at  Leeds,  England,  was  installed,  together  with 
the  other  equipment  to  make  up  a  complete  briquetting  plant. 
This  press  made  8-pound  briquets  and  had  a  capacity  of  7  to 
8  tons  per  hour.  A  White  press  of  the  Belgian  or  Loiseau  roll 
type  was  also  installed,  but  returned  to  the  owners  at  the  close 
of  the  exposition.  After  the  writer  was  placed  in  charge  of 
the  plant,  March,  1905,  the  die  plate  of  the  Johnson  press,  shown 
in  Fig.  2,  was  reduced  to  one-half  its  original  thickness  and 
other  improvements  were  made  in  order  to  briquet  larger  sam- 
ples of  coal,  such  as  were  subsequently  used  in  the  locomotive 
road  tests  discussed  further  on.  In  rebuilding  the  plant  in 
February,  1906,  the  first  operating  press  of  the  Renfrow 
Briquette  Machine  Co.  of  St.  Louis  was  installed,  making  a 
briquet  weighing  approximately  8  ounces  at  the  rate  of  6  to  7 
tons  per  hour.  While  this  press  embodied  all  the  fundamental 
principles  of  later  presses,  it  could  only  be  considered  an  ex- 
perimental press,  and  briquets  made  were  far  from  satisfac- 
tory. The  same  difficulties  were  experienced  as  may  be  found 
in  the  history  of  all  briquetting  presses  in  this  country  and 
abroad.  Insufficient  pressure  frequently  made  soft  briquets 
and  required  an  excess  of  binder  with  a  low  melting  point. 

Profiting  by  this  experience,  the  Renfrow  Company  built 
a  new  press  having  a  capacity  of  8  to  9  tons  per  hour,  and  mak- 
ing a  briquet  of  the  same  shape  weighing  13  ounces.  This 
press  was  installed  at  the  Norfolk  plant  of  the  Survey  and 
made  the  briquets  tested  on  the  eastern  railroads  and  for  the 
Navy  Department.  Upon  concluding  the  Norfolk  tests  the 
machine  was  sold  to  the  Rock  Island  Coal  Mining  Company  and 
installed  by  the  writer  at  Hartshorne,  Okla.  (See  Fig.  3).  The 
plant  has  been  operating  since  August,  1908.  part  of  the  time 
on  double  shift,  briquetting  the  bituminous  slack  mined  by  the 
company  and  marketing  the  product  for  domestic  purposes  in 
Oklahoma,  Arkansas  and  Texas  under  the  trade  name  of  "Car- 
bonets."  This  may  be  said  to  be  the  first  plant  in  the  Middle 
West  to  be  put  on  a  successful  commercial  basis.  The  success 
of  the  undertaking  is  largely  due  to  the  careful  consideration 
of  the  problems  involved  in  the  mechanical  construction  of  the 
plant,  the  binder  used  and  the  market  conditions  encountered. 

The  Western  Coalette  Fuel  Company  of  Kansas  City,  who 
used  a  Renfrow  press,  were  unsuccessful  because  these  prob- 
lems were  not  given  sufficient  consideration.    A  still  later  press 

Vol.  Ill,  No.  1]      BRIQUETTED  COAL:  MALCOLMSON 

of  the  Renfrow  Company  has  been  installed  by  the  Detroit 
Coalette  Fuel  Company  to  make  briquets  from  Pocahontas  coal 
for  domestic  purposes.  This  plant  was  completed  in  the  sum- 
mer of  1909. 

Kansas  City  is  being  supplied  again  this  winter  with  bri- 
quets by  the  Standard  Briquette  Fuel  Company  of  St.  Louis; 
the  plant  was  designed  and  built  at  Kansas  City  by  the  Roberts 
and  Schaefer  Company  of  Chicago,  using  a  Misner  press.  This 
press  is  of  the  plunger  type  having  a  capacity  of  ten  tons  per 

Fig.     3.       Renfrow    press    making    "Carbonets"    at    the    briquetting 
plant    of   the    Rock    Island    Coal    Mining    Co.,    Hartshorne,    Okla. 

hour.  Arkansas  semi-anthracite  and  hard  coke  oven  pitch  will 
be  used.  The  briquets  will  be  cylindrical  with  spherical  ends 
and  average  14  ounces  in  weight. 

Of  the  presses  so  far  available,  the  maximum  output  has 
been  about  ten  tons — with  the  possible  exception  of  the  Zwoyer 
press — in  making  briquets  of  4  pounds  and  less  in  weight.  If 
we  eliminate  the  binder,  the  cost  of  production  varies  directly 
with  the  output.  The  speed  of  reciprocating  press  of  the  Couf- 
finhal  type  is  fixed  by  the  time  required  to  move  the  die  plate. 
Rotary  presses,  of  the  Loiseau  type,  do  not  make  satisfactory 
briquets  larger  than  5  to  6  ounces.    Experience  has  shown  that 

THE    ARMOUR    ENGINEER  [Jan.,  1911 

for  railroad  fuel  made  from  bituminous  coal,  briquets  of  from 
2  to  4  pounds  each  give  best  results.  It  is  encouraging  to  learn 
that  there  is  being  tested,  at  an  Illinois  mine  near  St.  Louis,  a 
briquet  machine  which  is  a  new  departure  from  anything  so 
far  exploited  in  this  country,  bearing  some  relation  to  the  one 
manufactured  by  Flaud  et  Cie  of  Paris.  The  dies  are  filled  with 
the  same  accuracy  as  in  the  Renfrow  and  other  plunger  presses, 
and  the  compression  is  made  by  the  positive  action  of  plungers 
with  a  straight  line  motion,  but  there  are  no  reciprocating 
parts>  and  in  consequence  no  lost  motion.  This  press  has  a 
capacity  of  from  25  to  50  tons  per  hour,  and  is  capable  of 
making  briquets  from  2  ounces  to  20  pounds  in  weight  by 
changing  the  dies. 

No  effort  has  been  made  in  this  article  to  discuss  plants 
and  briquets  other  than  those  using  anthracite  or  bituminous 

An  excellent  study  of  the  treatment  of  Texas  lignites  has 
been  given  by  E.  T.  Dumble  in  a  "Report  on  the  Brown  Coals 
and  Lignite  of  Texas,"  in  which  he  states  the  earliest  efforts 
at  briquetting  were  made  by  the  Houston  and  Texas  Central 
Railway  in  1877.  The  International  Compress  Company,  the 
American  Lignite  Briquette  Company  and  the  Eureka  Bri- 
quette Company  of  Texas,  have  been  exploiting  the  briquetting 
of  lignite  with  binders,  while  the  Washburn  Lignite  Coal  Com- 
pany and  the  Northwestern  Briquet  Manufacturing  Company 
of  Minneapolis  have  been  experimenting  with  the  briquetting 
of  lignite  without  a  binder. 

Manufacturing   Process  and   Binders. 

The  briquets  which  we  shall  consider  are  made  by  pul- 
verizing the  coal,  already  of  the  proper  dryness,  adding  a 
binder,  mixing  the  mass  thoroughly  with  the  addition  of  suffi- 
cient steam  to  melt  or  moisten  the  binder  and  moulding  the 
agglomerate  in  specially  constructed  presses. 

In  the  briquetting  process,  the  most  expensive  item  of  cost 
is  the  binder,  and  every  conceivable  substance  or  mixture  hav- 
ing bonding  properties  has  been  proposed  for  this  purpose. 
Refuse  containing  starch  and  sugar,  sulphite  liquor,  clay  and 
lime  are  among  the  best  known.  Binders  soluble  in  water 
must  be  water-proofed  and  dried  before  being  handled,  a 
process,  which  is  usually  so  expensive  as  to  be  prohibitive.  The 
inorganic  binders  are  objectionable  on  account  of  the  addi- 
tional ash  and  clinker  added  to  the  fuel.  Deodorants  in  the 
form  of  compounds  of  chlorine  are  recommended  to  over- 
come the  odor  from  pitch  and  sulphur  during  combustion 
and  to    reduce    smoke,    but  their  value    is  doubtful.     Com- 

Vol.  Ill,  No.  1]      BRIQUETTED  COAL  :   MALCOLMSON  lb 

pounds  of  manganese  and  other  highly  oxygenated  com- 
pounds are  recommended  as  smoke  preventives,  where  coal 
tar  pitch  is  the  binder.  But.  except  in  special  instances, 
pitch  alone  is  used  which  is  made  from  tar  recovered  as  a  by- 
product in  the  destructive  distillation  of  coal,  from  by-product 
coke  ovens,  or  in  carburetting  water  gas  for  illuminating  pur- 

Since  the  binder  is  of  such  importance,  it  is  essential  that 
the  amount  be  reduced  to  a  minimum  and  that  it  be  thoroughly 
mixed  with  the  coal.  In  American  practice,  the  percentage 
of  pitch  required  varies  from  5  to  10%,  according  to  the 
process  used  and  the  coal  to  be  briquetted.  An  accuracy 
within  one  per  cent,  more  or  less,  seems  reasonable  from  a  me- 
chanical standpoint,  but  should  8%  be  the  amount  of  binder 
used  normally,  it  means  12%,  more  or  less,  in  the  cost,  which 
is  of  economic  importance. 

Briquetting  Pitch. 

In  the  fractional  distillation  of  coal  tar,  a  recovery  of 
65%  pitch  with  1.19  specific  gravity  is  a  fair  average.  On 
account  of  the  varying  demands  for  by-product  coke  oven  tar 
in  Europe,  the  quality  is  constantly  changing  at  the  different 
works.  In  this  country  the  lack  of  uniform  methods  and  the 
great  variety  of  coals  and  oil  used  present  the  same  difficulties 
in  obtaining  a  uniform  product.  Briquetting  pitch  should  be 
hard  enough  to  be  shipped  in  bulk  in  open  cars  and  remain  hard 
on  the  hottest  days.  To  effect  this  all  of  the  lighter  oils  and 
about  5%  of*  the  anthracene  should  be  extracted.  In  Europe 
the  pitch  becomes  soft  at  75°  and  melts  at  from  100°  to  120° 
C.  As  pitch  has  no  real  melting  point,  the  methods  used  in 
fixing  a  melting  point  are  arbitrary.  Following  the  methods 
established  by  the  Government,  and  in  use  here,  practice  has 
shown  that  a  pitch  with  a  melting  point  of  90°  C.  meets  the 
general  requirements.  Pitch  should  also  contain  as  little  free 
carbon  as  possible,  since  this  carbon  or  fine  dust  has  not  only 
no  binding  property  in  itself  but  requires  a  bond  to  hold  it 
together  in  the  briquet.  In  the  distillation  of  coal,  carried  on 
primarily  for  the  manufacture  of  gas  or  coke,  or  both,  the 
time  factor  in  the  process  determines  the  character  of  the  tar 
produced  as  a  by-product.  High  heats  "crack"  the  higher 
hydrocarbons  during  the  distillation,  producing  finely  divided 
free  carbon  which  remains  in  suspension  in  the  tar.  This  con- 
dition is  also  maintained  during  the  distillation  of  the  tar  in 
making  pitch.  Briquets  made  with  the  hard  pitch  usually 
sold  in  America  today,  are  brittle  and  produce  considerable 
slack  in  handling.    If  a  softer  grade  is  used,  the  briquets  are 



[Jan.,  1911 

Fig.  4.  Loading  briquets  direct  from  machine  to  car,  Government 
Coal  Testing  Plant,  Norfolk,  Va.  Briquets  made  from  Poca- 
hontas  coal  and  tested  on   U.   S.   S.   Connecticut. 

Tig.   5.     Another  view   of  conveying   belt   shown   in   Fig.   4   showing 
how  briquets  can  be  loaded  mechanically   without  breakage. 

Vol.  Ill,  No.  1]     BRIQUBTTED  COAL:  MALCOLMSON  15 

smoky,  and  have  a  disastrous  effect  on  the  faces  and  hands  of 
the  workmen.  To  overcome  these  difficulties,  experiments 
were  carried  on  at  the  Stockton  plant  and  a  binder  produced 
from  California  petroleum  that  was  both  hard  and  tough.  The 
Barrett  Manufacturing  Company  has  for  some  time  recognized 
the  importance  of  a  satisfactory  "briquetting  pitch"  and  is 
now  prepared  to  market  a  product  following  specifications 
already  suggested  by  the  writer. 

Handling  and  Breakage. 

One  of  the  principal  problems  which  confronts  producers 
and  users  of  coal,  and  particularly  the  railroads,  is  the  deterior- 
ation of  its  fuel  in  handling  and  storing.  Bituminous  coal 
cannot  be  handled  without  breakage,  which  assumes  a  very 
considerable  percentage  even  in  well  designed  coaling  stations. 
This  is  more  noticeable  in  the  friable,  low  volatile  coals.  Eng- 
lish statistics  show  that  with  Welsh  bunker  coal  the  waste  in 
handling  is  2  to  3%,  and  the  breakage  20  to  30%,  which  aften 
reaches  50%  in  rough  weather.  The  cohesion  of  briquets  made 
in  South  Wales  show  83%,  against  40%  for  the  same  coal  in 
lump  form  for  which  the  breakage  was  .88%  for  briquets  and 
2.13%  for  coal.  It  has  been  observed  by  a  mechanical  engineer 
of  a  western  railroad  that  the  percentage  of  dust  in  handling 
briquets  three  times  should  not  exceed  8%. 

Figs.  4  and  5  show  the  manner  of  handling  briquets  direct 
from  machine  to  ear,  and  the  absence  of  slack  in  the  car  is 
apparent.  Fig.  6  shows  a  carload  of  briquets  made  from  Po- 
cahontas coal  being  delivered  to  a  navy  barge  at  Norfolk.  Fig. 
7  is  from  a  photograph  taken  thirty  seconds  after  the  one  shown 
in  Fig.  6,  and  is  further  evidence  of  the  small  amount  of  break- 
age which  we  may  expect  from  well-made  briquets.  The -drop 
from  bottom  of  car  to  deck  of  barge  is  about  15  feet.  These 
pictures  further  illustrate  the  rapidity  with  which  this  form 
of  fuel  may  be  handled  in  coaling  stations.  It  requires  about 
20  minutes*  to  unload  a  similar  self-clearing  car  of  coal  at  the 
Norfolk  and  Western  coaling  piers  at  Lambert's  Point,  aij  item 
of  considerable  importance  in  bunkering  a  ship. 

In  all  locomotive  tests,  referred  to  later,  where  the  briquets 
were  reasonably  well  made,  the  breakage  in  handling  was  neg- 
ligible; and  the  results  of  other  tests  made  at  the  St.  Louis 
pfant  bear  out  the  European  experience.  The  percentage  of 
slack  in  handling  was  approximated  by  a  series  of  experiments 
known  as  "drop  tests,"  in  which  50  pounds  of  briquets  were 
three  times  dropped  a  distance  of  6V?  feet  on  a  cast-iron  plate, 
and  the  percentage  of  broken  briquets  recorded  which  was 



[Jan.,  1911 

Fig.  6.  Briquets  being  loaded  on  Government  barge  at  Norfolk 
for  test  on  U.  S.  S.  Connecticut.  This  photograph  was  taken 
as    hoppers    were    opened. 

Fig.  7.  View  taken  30  seconds  later  than  that  shown  in  Fig.  6, 
showing  rapidity  with  which  this  form  of  briquet  can  be  dis- 
charged from  hoppered  bottom  cars  and  without  breakage.  It 
takes  20  minutes  to  unload  lump   coal  from   same  car. 

Vol.  Ill,  No.  1]      BRIQUETTED  COAL:   MALCOLMSON 


retained  on  a  1-inch  square  mesh  wire  screen.  These  results 
were  used  to  check  the  tumbler  tests,  similar  to  those  made 
in  Europe  to  determine  the  cohesion  of  the  briquet.  Fig.  8 
shows  the  relative  cohesion  of  briquets,  coke  and  lump  coal 
after  being  subjected  to  the  tumbler  tests.  It  was  found  that 
the  constant  jarring  of  the  fuel  on  locomotive  tanks  created 
considerable  slack  when  the  briquets  were  badly  made.  The 
tumbler  tests  approximated  the  results  obtained  in  practice. 
If  the  briquets  were  well  made,  the  cohesion  was  greater  and 
the  erosion  less  than  with  the  same  coal  in  lump  form.  Break- 
age not  only  produces  a  poorer  locomotive  fuel  but  increases 
the  losses  due  to  wastage  or  otherwise  unaccounted  for. 


8.      Showing   the   relative   cohesion    of   briquets,   coke   and   lump    coal, 
having:    been    subjected    to    the    tumbler    test. 

No.  1. 

No.  2. 

No.  3. 

No.  4. 

West    Virginia    coke. 

Round  briquet  made  of  Arkansas  coal. 
Square  briquet  made  of  Arkansas  coal. 
Southern    Illinois    lump    coal. 


In  countries  where  labor  is  cheap,  large  prismatic  briquets 
are  used  because  they  can  be  easily  stacked  by  hand,  and 
occupy  less  bunker  space.  For  this  reason  the  French  Navy 
specifies  large  briquets  with  an  estimated  bunker  capacity  of 
51  pounds  per  cubic  foot  or  10%  less  than  for  coal.  With  the 
increased  calorific  value  this  is  of  supreme  importance  by  in- 
creasing the  steaming  radius  of  the  vessel.  The  British  Ad- 
miralty reports  20%  increased  steaming  radius.  The  briquets 
in  this  form,  however,  require  twice  as  long  to  coal  as  with 
the  raw  fuel.  In  India  and  the  West  Indies  28-pound  briquets 
are  used  because  one  constitutes  a  load  for  a  native.  It  was 
shown  at  the  government  tests  at  Norfolk  that  as  much  as 



[Jan.,  1911 

Fig.  9.  This  car  was  originally  full  of  coal,  approximately  one- 
half  of  which  was  taken  out,  briquetted  with  6  per  cent  hinder 
and  returned  to  car.  This  illustration  shows  the  reduced 
hunker    capacity    required    by    briquets. 

Fig    10.      Carload   of  "Carbonets''   at    Hartshorne,   Okla. 

Vol.111,  No.  1]      BRIQUETTED  COAL:  MALCOLMSON 

20%  increased  space  was  required  when  prismatic  briquets 
were  loaded  without  stacking.  Fig.  9  illustrates  the  reduced 
bunker  capacity  of  briquets  over  that  required  for  coal.  This 
car  originally  contained  a  maximum  load  of  coal,  approxi- 
mately one-half  of  which  was  briquetted  and  returned  to  the 
car.  The  briquets  made  at  the  Hartshorne  plant  loaded  to 
capacity  on  gondola  or  dump   cars  will  weigh   within   10   to 

Fig.  11.  Samples  of  briquets  taken  from  open  storage  piles  at  the  Government 
Fuel  Testing  Plant,  St.  Louis,  after  3  years'  exposure.  In  each  sample  one 
briquet  was  taken  from  surface  and  interior  of  pile  to  show  effect  of 
weathering.  In  sample  108,  110.  118,  120  and  128  the  briquets  were  made 
with  coal  tar  pitch  binder.  These  briquets  were  made  on  the  Johnson 
press    during    1904    and    weigh    8    pounds. 

15%  as  heavy  as  mine  run  coal,  or  about  equal  to  egg  size,  as 
shown  in  Fig  10.  No  difficulty  was  experienced  in  loading  box 
cars  to  capacity  plus  10%. 


It  has  been  observed  that  carefully  executed  tests  in 
Europe  show  nearly  30%  of  the  heating  value  of  coal  is  lost 
when  stored  in  open  piles,  while  English  naval  records  have 



[Jan.,  1911 


12.       Briquets    made    from     Pennsylvania    coal    after    three    months'    open 
storage.      The    broken    briquets    show    the   character   of   fracture. 

Fig.  13.  Briquets  made  from  raw  Kansas  slack  after  three  months'  storage 
in  the  open  during  the  winter.  This  slack  is  high  in  sulphur  and  cannot 
be    stored   without   "firing." 

Vol.  Ill,  No.  1  ]     BRIQUETTED  COAL :  MALCOLMSON  21 

mentioned  that  it  required  from  50  to  100%  more  stored  coal 
to  operate  vessels  than  when  freshly  mined,  coal  is  used. 

Experiments  made  in  this  country  show  that  about  10% 
depreciation  may  be  expected  from  coal  stored  in  the  open 
and  that  housing  only  helps  the  situation  where  the  coals  are 
high  in  sulphur. 

Fig.  11  represents  samples  of  briquets  taken  from  open 
storage  piles  at  the  Government  Fuel  Testing  Plant,  St.  Louis, 
after  three  years'  exposure.  In  each  sample  a  briquet  was 
taken  from  surface  and  interior  of  pile  to  show  effect  of  weath- 
ering. In  samples  108,  110,  118,  120  and  128  the  briquets  were 
made  with  coal  tar  pitch  binder.  These  briquets  were  made 
on  the  Johnson  press  during  1904  and  weigh  8  pounds.  An- 
alyses of  these  samples  show  practically  no  loss  in  calorific 
value.  In  Fig.  12  one  of  the  outer  briquets  was  broken  to 
show  the  character  of  the  fracture.  These  briquets  show  no 
deterioration  after  three  months'  storage  in  open  pile.  The 
briquets  shown  in  Fig.  13  were  made  from  a  high  sulphur  coal 
that  cannot  be  stored  without  igniting  from  spontaneous  com- 
bustion, particularly  if  exposed  to  the  weather. 

Mr.  W.  H.  V.  Rosing,  mechanical  engineer  of  the  Missouri 
Pacific  Railway,  states  that  "it  is  our  practice  to  store  coal 
during  the  summer  months  when  the  coal  cars  on  the  system 
are  not  being  fully  utilized,  and  use  coal  from  storage  piles 
later  in  the  season  when  all  the  cars  are  required  for  com- 
mercial use.  In  this  manner  several  hundred  thousand  tons 
are  stored  annually.  During  the  summer  of  1907  we  lost.  14,- 
400  tons  of  coal  by  spontaneous  combustion  alone,  which 
amounted  to  8V2%  of  the  total  stored.  In  fact  we  can  only 
store  coal  from  certain  mines  on  the  system,  and  this  must  be 
stored  in  a  certain  manner  to  avoid  loss  by  spontaneous  com- 
bustion. With  the  briquetted  fuel  we  could  store  coal  from 
any  of  the  mines  without  danger  of  spontaneous  combustion, 
without  deterioration  or  loss  of  volatile  combustibles  which 
occurs  on  the  surface  of  the  ordinary  coal  piles." 

Mr.  A.  W.  Gibbs,  G.  S.  M.  P.,  Pennsylvania  Railroad, 
makes  the  following  statement  in  his  report  of  briquet  tests 
at  Altoona: 

"To  observe  the  effect  on  briquets  of  exposure  to  the 
weather  a  number  of  the  round  and  square  briquets  were 
placed  on  the  roof  of  the  testing  plant.  After  four  months  of 
exposure  for  the  round  and  three  months  for  the  square 
briquets  no  change  whatever  from  their  original  condition  was 
noticed.  They  appeared  to  be  entirely  impervious  to  moisture 
and  were  still  firm  and  hard. 

22  THE    ARMOUR    ENGINEER  [Jan.,  1911 

"The  briquets  were  little  affected  by  handling.  They  were 
loaded  at  St.  Louis  in  open  gondola  cars  and  shipped  to  Al- 
toona,  where  they  were  unloaded  by  hand  and  stacked.  They 
were  handled  a  third  time  in  taking  them  to  the  firing  plat- 
form of  the  test  locomotive.  After  these  three  handlings  they 
were  still  in  good  condition,  very  few  were  broken,  and  the 
amount  of  dust  and  small  particles  was  practically  negligible." 

Briquets  Used  on  European  Railroads. 

Practically  all  of  the  European  railroads  use  briquets  and 
the  quantity  varies  from  15  to  40^  of  the  total  coal  consumed. 
The  briquets  for  railway  and  steamship  use  are  prismatic  in 
shape.  The  French  navy  specifies  22-pound  briquets.  These 
briquets  are  broken  before  firing,  and  if  well  made  will  break 
into  pieces  without  making  dust.  The  railroads  use  briquets 
not  to  exceed  11  pounds  in  weight,  which  are  fired  one  or  more 
at  a  time  by  hand.  Storage  fuel  is  usually  in  the  form  of 
briquets;  they  are  carried  on  the  tanks  along  with  coal  and 
generally  used  to  get  up  steam,  to  make  up  time,  or  over  heavy 
grades  during  the  run. 

The  specifications  to  contractors  furnishing  briquets  to  the 
state  railroads  on  the  continent  are  very  rigid,  particularly  in 
France.  These  specifications  vary  somewhat  in  the  different 
countries  but  are  covered  generally  by  the  following  items : 

1st.  Briquets  shall  be  well  made,  sonorous,  entire,  with 
sharp  edges,  breaking  with  a  clean  cut,  brilliant  and  homoge- 
neous fracture. 

2d.  Their  cohesion  shall  not  be  less  than  55%  and  they 
shall  not  soften  at  50°  C. 

3d.  The  briquets  shall  ignite  easily  without  causing  dense 
black  smoke,  shall  burn  with  a  quick  bright  flame  and  be  'con- 
sumed without  disintegrating.  The  slag  or  clinker  shall  not 
adhere  to  the  grates  or  tube  sheets. 

4th.  The  briquets  shall  not  be  hygroscopic  nor  contain 
more  than  4%  moisture.  They  shall  contain  between  15  and 
22%  volatile  combustible,  and  not  more  than  11%  ash.  The 
coal  shall  have  been  freshly  mined  and  free  from  sulphur. 

5th.  Coal  tar  pitch  is  the  only  binder  specified;  it  must 
be  practically  odorless  and  limited  to  10%. 

6th.  The  briquets  must  be  prismatic  with  a  square  base; 
when  specified  they  are  from  3  to  11  pounds  in  weight,  accord- 
ing to  kind  of  coal  used,  with  a  density  of  from  1.13  to  1.21. 

Work  of  Government   Plant  at  St.  Louis. 

During  1905,  1906  and  1907,  over  one  hundred  tests*  were 

♦Published   by  permission  of  Director,  TJ.   S.   Geological  Survey. 

Vol.  Ill,  No.  1]     BRIQUETTED  COAL:   MALCOLMSON  23 

conducted  by  the  government  on  eastern  and  western  rail- 
roads to  establish  the  relative  value  of  briquetted  and  raw 
coal  for  locomotive  use.  Seventy  road  tests  were  made  on  the 
Burlington,  Rock  Island.  Missouri  Pacific  and  Chicago  & 
Eastern  Illinois  Railways,  and  twenty  tests  at  the  Altoona 
laboratory  of  the  Pennsylvania  Railroad,  under  the  direction 
of  the  writer,  assisted  by  G.  E.  Ryder  and  Ralph  Gait.  The 
co-operation  of  all  the  railroad  officials  was  secured  so  that 
these  tests  would  be  of  value  to  them  in  comparison  with  other 
locomotive  fuel  tests.  An  abridgment  of  Mr.  E.  D.  Nelson's 
report  on  the  Pennsylvania  laboratory  tests  has  been  publisbed 
in  Bulletin  No.  363  of  the  Survey. 

The  briquets  were  made  at  the  Fuel  Testing  plant  at  St, 
Louis,  and  the  details  of  manufacture  have  already  been  re- 
ported in  Bulletin  No.  332  of  the  U.  S.  Geological  Survey.  The 
object  of  the  road  tests  was  to  discover,  if  possible,  the  prob- 
lems to  be  encountered  in  the  use  of  briquets  in  actual  practice 
and  wherein  this  practice  was  affected  by  good  or  faulty  manu- 
facture of  the  fuel.  It  must  be  remembered  that  the  best 
efforts  at  the  St.  Louis  plant  could  not  produce  uniformly  sat- 
isfactory briquets.  The  English  machine  was  designed  to  meet 
European  requirements  and  the  American  machine  was  in  an 
experimental  stage  and  made  at  best  a  product  of  varying 
quality.  The  problems  involved  in  the  manufacture  of  briquets 
from  our  coals  have  been  already  reported.  It  is  one  object 
of  this  article  to  show  their  value  for  railroad  use. 

Locomotive   Road  Tests. 

The  first  locomotive  tests  were  made  during  the  autumn 
of  1905  on  locomotives  of  the  Missouri  Pacific  Railroad  between 
St.  Louis  and  Sedalia,  after  having  tested  the  burning  quality 
of  the  briquets  in  stationary  locomotive  boilers.  The  briquets 
were  made  on  the  Johnson  machine  from  Arkansas  semi-an- 
thracite slack,  and  were  tested  in  comparison  with  the  Illinois 
lump  coal  regularly  furnished  for  that  division.  The  results 
given  in  a  report  by  W.  H.  V.  Rosing  indicate  an  increased 
evaporation  of  23%  and  a  decreased  consumption  of  fuel  per 
1,000  ton  miles  of  37%  in  favor  of  the  briquets.  The  briquets 
were  broken  in  halves  on  this  test,  which  created  about  20% 

About  this  time,  the  New  York  Central  Lines  became  in- 
terested in  the  use  of  briquetted  coke  breeze,  and  burned  some 
briquets  made  at  the  plant  on  the  same  machine.  These 
bricpiets  were  tested  in  freight  and  switching  service  by  the 
Lake  Shore  Railroad  near  Cleveland.  The  report  of  Mr.  H. 
F.  Ball,  Superintendent  of  Motive  Power,  indicates  that  the 



[Jan.,  1911 

Fig.  14.  Shows  two  suburban  trains  on  the  Rock  Island  passing: 
each  other  in  the  yards  north  of  Englewood.  The  locomotive 
to    the    right    is    burning    briquets. 


15.     Illustrates  the  characteristic  puff  of  smoke  lasting:  3  to  5 
seconds  which  appears  directly  after  firing-. 

Vol.111,  No.  1]      BRIQUETTED  COAL:   MALCOLMSON  25 

briquets  were  not  satisfactory  for  heavy  service,  but  had  some 
advantages  for  switching,  owing  to  the  entire  absence  of  black 
or  gray  smoke  and  very  few  cinders.  The  briquets  were  hard 
to  ignite,  which,  added  to  the  high  ash  content  of  the  coke, 
and  the  size  of  the  briquets,  made  it  difficult  to  maintain  a 
good  fire. 

Briquets  made  from  mixtures  of  gas-house  coke  and  Illinois 
screenings  were  tested  in  switching  service  by  the  Missouri 
Pacific  Railroad  at  St.  Louis.  The  briquets  gave  better  results 
than  the  ones  made  from  coke  oven  breeze.  Even  with  those 
containing  50%  coal,  however,  there  was  always  an  interval 
of  time  directly  after  firing  when  the  steam  pressure  would 
fall.  If  the  engine  was  working  this  was  objectionable.  No 
smoke  was  discernible  even  when  the  blower  was  shut  off. 

In  June,  1906,  the  Rock  Island  Railroad  became  interested 
in  the  use  of  briquets  and  100  tons  of  Hartshorne,  I.  T.,  slack 
were  briquetted  and  shipped  to  Chicago  for  test.  The  report  of 
C.  A.  Seley  compared  these  results  with  Illinois  lump  coal 
used  in  freight  service  and  indicated  an  average  in  the  coal 
consumption  of  26.2%  in  favor  of  briquets.  The  observer's 
notes  on  these  tests  state  that  "the  briquets  did  not  'honey- 
comb' the  tube  sheets  sufficiently  to  give  any  trouble  and  this 
slag  was  not  as  hard  to  remove  as  with  Illinois  coal.  The 
ashes  from  the  briquets  did  not  clinker.  The  nozzle  could  be 
increased  *4  incn  an(*  still  produce  a  sufficient  draft.  This 
fuel  burns  with  an  intense  heat,  much  like  coke,  and  the  depth 
of  the  fire  is  easily  regulated.  On  arriving  at  Joliet,  an  in- 
spection showed  fire  next  to  the  grate  which  would  not  be  the 
case  with  coal.  A  slight  puff  of  black  smoke  appeared  only 
when  briquets  were  fired ;  this  almost  immediately  disappeared 
— a  desirable  feature  for  suburban  service." 

Fig.  14  shows  two  suburban  trains  on  the  Chicago,  Rock 
Island  and  Pacific  Railway  passing  each  other  in  the  yards 
north  of  Englewood.  They  are  both  running  at  full  speed. 
The  approaching  train  is  burning  coal. 

Fig.  15  illustrates  the  characteristic  puff  of  smoke  which 
appears  directly  after  firing  briquets  and  lasts  three  to  five 
seconds ;  engine  is  on  Chicago,  Rock  Island  &  Pacific  suburban 
service  approaching  Morgan  Park  at  full  speed.  Fig.  16  shows 
engine  standing  at  Walden,  blower  off;  and  Fig.  17  shows 
engine  approaching  Tracy  at  full  speed. 

The  general  interest  awakened  by  these  preliminary  tests 
warranted  the  government  in  making  more  extensive  records, 
and  the  co-operation  of  the  Rock  Island,  Missouri  Pacific,  Bur- 
lington and  Chicago  &  Eastern  Illinois  Railroads  was  sought  to 

26  THE    ARMOUR    ENGINEER  [Jan.,  1911 

Fig.   16.      Shows   Rook    Island   suburban   engine   standing  at   Walden 
with   blower   shut    off. 

Fig.   17.     Shows  engine   of  same  train  approaching   Tracy   at  full  speed. 

Vol.  Ill,  No.  11      BRIQUETTED  COAL:  MALCOLMSON  27 

this  end.  The  samples,  varying  in  weight  from  100  to  400  tons, 
were  shipped  to  St.  Louis  and  briquetted  on  the  English  and 
Renfrow  machine  in  about  equal  amounts,  using  from  6  to  9% 
of  water  gas  pitch  binder.  The  briquets  were  consigned  to  the 
railroad  and  loaded  through  its  coal  chutes  in  the  usual  man- 
ner in  which  coal  is  handled.  Where  the  briquets  were  soft,  care 
was  taken  to  handle  them  with  coke  forks  in  weighing  onto  the 
tender.  The  water  tanks  were  calibrated  and  the  water  meas- 
ured as  used.  Flue  gas  analyses  and  front  end  and  furnace 
temperatures  were  taken  during  the  run.  Careful  selected 
samples  of  fuel,  ash  and  cinders  were  shipped  to  St.  Louis 
and  anaylzed.  Steam  pressure,  feed  water  temperature,  leak- 
age, smoke,  condition  and  thickness  of  fuel  bed,  method  of 
firing  and  draft  were  recorded.  The  same  engine,  and,  as 
nearly  as  possible,  the  same  crew  were  furnished  by  the  rail- 
road for  all  tests  on  that  road.  At  the  end  of  the  run  the 
condition  of  the  engine  was  noted,  and  the  test  written  up. 

Comparative  tests  were  made  on  lump  coal  from  the  same 
mines  as  the  slack  shipped  from  Oklahoma,  Kansas  and  Mis- 
souri. A  condensed  summary  of  the  results  of  these  tests  is 
given  below.  A  record  of  tests  on  Carterville  lump  and  mine 
run  coal  made  by  the  Burlington  Railroad  is  included  for  com- 
parison with  the  tests  of  briquetted  slack  from  the  same  district. 

The  foregoing  report  is  condensed  from  a  data  sheet  in 
which  a  total  of  122  observed  and  calculated  items  made  up  the 
record  of  each  test.  Averages  of  all  tests  made  on  each  kind 
of  fuel  are  given,  as  for  obvious  reasons  it  is  desirable  to 
abridge  the  report.  Noting  the  equivalent  evaporation  per 
pound  of  fuel  as  fired,  it  will  be  observed  that  in  nearly  all 
eases  the  rate  is  in  favor  of  briquets. 

In  the  case  of  the  tests  of  Illinois  coal  on  the  Burlington 
Railroad,  all  of  the  fuels  are  from  different  mines  and  are 
therefore  of  comparative  value  only  when  their  cost  is  taken 
into  account.  Tests  of  Illinois  coal  on  the  Missouri  Pacific 
Railroad  are  omitted  because  of  no  comparative  tests  on  lump 
coal.  The  Burlington  tests  with  Missouri  coal  show  practically 
the  same  results  with  briquets  and  lump  coal,  while  the  Indi- 
ana coals  offer  the  same  problems  in  briquetting  and  show 
the  same  characteristics  in  burning  as  Illinois  coals. 

The  most  representative  tests,  and  therefore  the  most 
accurate  expression  of  what  may  be  accomplished  with  well 
made  briquets,  are  the  tests  made  on  the  Rock  Island  and  Mis- 
souri Pacific  Railroad  with  Oklahoma  and  Kansas  coals.  The 
Rock  Island  tests  show  an  increase  equivalent  evaporation  of 
8%   and  increased  boiler  efficiency  of  about  15%,  while  the 









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Vol.  Ill,  No.  1]     BRIQUETTED  COAL:  MALCOLMSON  29 

Kansas  briquets  show  25%   increased  evaporation  and  boiler 
efficiency  over  lump  coal.  The  causes  to  which  may  be  attributed 
the  variation  in  results  of  the  various  fuels  tested  are  discussed 
further  on. 
Altoona  Laboratory  Tests. 

In  a  testing  plant,  such  as  is  maintained  by  the  Pennsyl- 
vania Railroad  at  Altoona,  careful  regulation  and  accurate 
comparative  data  are  obtainable  under  varying  conditions  of 
engine  and  boiler  performance.  This  data  is  valuable  in  afford- 
ing results  which  may  be  at  least  approximated  under  the  best 
road  conditions  in  practice.  The  fact  that  they  compare  fav- 
orably with  the  road  tests  is  encouraging.  The  briquets  used 
were  manufactured  at  the  St.  Louis  plant  from  a  low  volatile 
high  grade  friable  coal  in  the  form  of  mine  run,  mined  in 
Cambria  county,  Pennsylvania.  About  equal  proportions  of 
square  and  round  briquets  were  made  with  5,  6,  7  and  8%  water 
gas  pitch  binder.  The  same  coal  in  mine  run  form  was 
shipped  to  the  Altoona  plant  for  comparative  tests.  As  this 
coal  is  used  by  the  Pennsylvania  Railroad,  its  characteristics 
as  a  locomotive  fuel  were  well  known.  The  principal  objection 
to  its  use  was  the  large  percentage  of  fuel  lost  through  the 
stack  as  fine  coke,  which  amounted  to  as  much  as  23%  when 
operating  under  heavy  load.  To  this  may  be  added  the  front 
end  cinder,  which  greatly  obstructed  the  draft.  The  coal  pro- 
duces less  smoke  than  other  coals  used  on  the  system  and  this 
feature  made  it  a  valuable  fuel  for  fast  passenger  and  terminal 
service.  The  object  of  these  tests  was  to  determine  what  effect 
briquetting  would  have  on  these  characteristics,  and  in  addi- 
tion, on  boiler  efficiency  and  capacity.  Tests  were  made  at  4 
or  5  rates  of  combustion  for  each  kind  of  briquet  and  the  mine 
run  coal,  starting  with  30  pounds  of  coal  per  square  foot  of 
grate  surface  per  hour  and  running  to  the  maximum  capacity 
of  the  boiler.  The  maximum  rate  with  coal  was  102  pounds, 
against  127  pounds  for  briquets,  an  increase  of  25%. 

The  comparison  of  coal  and  briquets  at  equal  rates  of  com- 
bustion, shows  an  average  increase  in  boiler  efficiency  of  about 
15%  and  an  increased  equivalent  evaporation  of  20%  in  favor 
of  briquets  for  the  different  rates  compared: 
Evaporation    per 

sq.  ft.  of  Heating 

Equivalent  Evaporation 

per  pound  of 

Surface  per  hour. 

Raw  Coal. 


8  pounds 

9.5  pounds 

10.7  pounds 

10       " 

8.8      " 

10.2       " 

12      " 

8.0      " 

9.7       " 

14      " 

7.3      " 

9.2      " 

16      " 

6.6      " 

8.7      " 

THE    ARMOUR    ENGINEER  [Jan.,  1911 




NalsMS«                      |,m  40—M.                             NO.O                                   •      |—»J»                                  No0                                        i-    -,o 



(Mo  o                                   1-3S 

No.Tb                                 7»o-«^ 

No.o                          -2-os. 



No  1                            -:    '  o 

No   O                                   -2-15 

No   O                                  2-2.© 



NoO                                  2--2B 

NpO                                        2-3Q                                   No  O                                       2-35 


V      . 

No.o                             7-40 

No.o                          a- so 

No.l                                  2-55 



No.O                           3«o^,«a 

NO.O                        AT  WOP 

No.l              s^o^y^ 

Figr.    18.      Smoke    observations    taken    every    5    minutes    during    test    of    briquets 
at  testing  laboratory   of  Pennsylvania   R.   R.  at  Altoona. 

Vol.  Ill,  No.  1]      BRIQUETTED  COAL  :  MALCOLMSON  31 

In  comparing  the  coal  consumed  per  dynamometer  horse- 
power per  hour,  with  the  total  power  developed,  the  record 
showed  a  difference  of  nearly  35%  in  favor  of  the  briquets, 
when  the  engine  was  working  most  efficiently.  This  figure 
compares  favorably  with  data  obtained  from  road  tests  on  the 
coal  consumption  per  ton  mile. 

Smoke  readings  were  taken  at  stated  periods  during  each 
test  and  the  density  stated  in  terms  of  Ringlemann's  charts. 
Based  on  5  as  representing  very  black  smoke,  the  average  of 
all  readings  for  coal  was  1.5,  for  round  briquets  0.9  and  for 
square  briquets  0.6,  or  in  other  words  the  coal  made  twice 
as  much  smoke  as  the  briquets.  Fig.  18  shows  a  series  of 
photographs  of  the  stack  at  Altoona,  taken  every  5  minutes 
during  the  test.  The  average  smoke  record  for  this  test  was 

Importance  of  Physical  Characteristics  of   Fuel. 

When  a  sample  of  coal  is  burned  in  a  calorimeter,  all  of  the 
combustible  is  consumed  and  the  total  heat  value  of  the  fuel 
is  given  in  British  Thermal  Units.  In  practice  this  result  can 
only  be  approximated,  since  there  will  always  be  a  loss  in  the 
stack  gases,  by  radiation  and  in  the  fuel  left  unburned  in  the 
refuse.  The  efficiency  of  the  furnace  as  a  heat  producer  and 
of  the  boilers  as  a  heat  absorber  play  an  important  part.  The 
real  value  to  the  consumer  is  the  evaporation  possible  in  actual 
practice.  The  purchase  of  coal  on  a  B.  T.  U.  basis  is  an  im- 
provement over  the  old  method  that  "coal  was  coal"  and  the 
lowest  prrce  made  the  cheapest  fuel.  The  physical  character 
of  the  coal  as  delivered  on  the  locomotive  tank  and  its  be- 
havior in  the  fire  during  all  conditions  met  with  on  the  road  is 
often  of  more  importance  than  its  theoretical  heat  value.  An 
official  of  the  Pennsylvania  Railroad  once  told  the  writer  that 
his  company  could  afford  to  pay  the  same  price  for  a  certain 
coal  of  higher  ash  content  and  consequent  lower  heating  value 
than  for  a  much  cleaner  and  theoretically  superior  coal,  because 
the  poorer  coal  made  an  ash  which  did  not  clinker  and  was 
easily  shaken  through  the  grates. 


Coal  will  burn  only  where  there  is  sufficient  air  in  the 
presence  of  an  ignition  temperature;  and  the  rate  of  combus- 
tion is  usually  limited  by  the  air  supply  and  the  ability  to  mix 
it  with  the  gases  from  the  coal.  When  a  lump  of  coal  burns, 
the  tendency  is  for  the  gases  to  pass  off  through  the  lines  of 
least  resistance,  that  is,  from  the  crevices  made  in  the  coal  as 
it  breaks  up  in  the  fire.     In  the  ease  of  briquets  there  is  no 



[Jan.,  1911 

tendency  to  do  this,  owing  to  their  homogeneous  and  porous 

If  we  examine  a  briquet  in  the  process  of  burning,  as  in 
Fig.  19,  we  find  that  it  burns  entirely  from  the  outside.  As  the 
volatile  combustible  is  driven  off,  a  layer  of  coke  is  formed 
which  burns  to  ash  and  falls  off  or  is  carried  away  by  the  draft. 
Thus  we  find  successive  layers  showing  partial  combustion  of 
the  fuel  while  the  inner  part  is  unaffected,  and  the  briquet 
retains  its  identity  as  such  until  entirely  consumed. 

The  density  of  the  briquet  is  of  prime  importance.  Harder 
briquets  do  not  break  up  so  easily  and  they  burn  more  slowly 

Fig.  19.  Briquets  made  from  Hartshorne,  Okla.,  coal  showing  various  stages 
of  combustion.  The  smaller  briquets  were  made  on  Renfrow  press  and 
weigh  8  oz.  each.  The  larger  briquets  were  made  on  Johnson  press  and 
weigh  4  lbs.  each.  No.  8  shows  the  interior  of  the  briquet  intact,  and 
outside  layer  of  coke.  The  depth  of  the  coking  is  shown  in  No.  7.  In 
No.  9  the  briquet  has  been  reduced  nearly  to  ash.  The  briquets  swell 
slightly  in  burning  and  their  efficiency  is  largely  due  to  the  uniformity 
with  which  the  gases  are  delivered  from  the  surface  of  the  briquet,  and 
mix    with    the    air. 

in  the  fire.  By  this  means  the  volatile  combustible  is  driven 
off  more  nearly  at  the  rate  at  which  it  can  be  burned  with 
greatest  economy,  and  the  briquets  form  coke  during  the 
process  of  combustion  even  though  made  with  an  otherwise 
non-coking  coal.  This  is  more  essential  with  high  volatile  than 
with  high  carbon  coals. 

With  the  harder  volatile  coals  of  Illinois,  the  tendency  of 
the  lump  coal  to  break  up  in  the  fire  is  less  than  with  the  more 
friable  low  volatile  coals  of  the  Appalachian  field.  The  east- 
ern coals  also  produce  much  more  slack  in  handling  so  that  the 
main  objection  to  their  use  as  a  railroad  fuel  is  the  percentage 
lost  through  the  stack  and  the  coking  of  the  coal  in  a  mass  in 
the  firebox.     The  Arkansas  and  Oklahoma  coals  have  similar 

Vol.  Ill,  No.  1]     BRIQUETTED  COAL  :  MALCOLMSON  33 

characteristics.  With  well  made  briquets  from  these  good 
coking  coals,  the  briquets  coke  separately  and  do  not  run  to- 
gether in  the  fire.  It  was  thought  necessary  to  break  the 
Arkansas  four-pound  briquets  before  firing,  but  the  same 
briquets  made  from  Hartshorne  and  Loydell  coals  were  fired 
whole  and  burned  with  good  results.  The  eight-ounce  briquets 
did  not  give  as  loose  a  fire  and  could  not  be  fired  with  such  a 
heavy  bed  when  made  from  Illinois  coal.  It  must  be  observed 
in  this  connection,  however,  that  the  more  friable  coals  can  lie 
made  into  better  briquets  with  less  pressure  than  the  other 
coals  tested. 

The  whole  value  of  the  briquet  is  clue  to  its  uniform 
size  and  freedom  from  slack  in  handling.  These  statements 
are  borne  out  in  the  tests  of  Illinois  and  Missouri  coals, 
where  the  lump  coal  did  not  break  up  badly  in  handling,  while 
the  briquets  used  on  these  tests  produced  at  least  15%  slack, 
which  was  naturally  very  fine;  a  considerable  portion  being 
lost  through  the  stack.  The  fuel  could  not  be  "wet  down"  as 
uniform  conditions  had  to  be  maintained  for  test  purposes. 
These  coals  do  not  readily  coke  so  that  while  a  poorly  made 
briquet  would  hold  together,  if  made  from  the  eastern  coal,  it 
would  tend  to  disintegrate  when  made  from  these  coals.  It 
was  therefore  necessary  to  fire  with  a  thin  bed  as  the  fine  coal 
would  cause  heavy  clink  to  form  and  cut  off  this  draft  when 
a  thick  fire  was  carried.  It  was  the  usual  experience  that  the 
briquets  made  no  objectionable  clinker  and  the  ash  was  finely 
divided  and  easily  shaken  through  the  grates.  This  is  to  be 
expected  from  the  manner  in  which  the  coal  is  prepared  before 
briquetting,  and  from  the  uniform  distribution  of  the  slag 
producing  elements  of  the  ash,  such  as  iron  pyrites,  throughout 
the  briquet. 
Smoke  and  Cinders. 

The  reduction  in  cinders  and  sparks  by  briquetting  depends 
on  the  quality  of  the  coal  as  well  as  the  density  of  the  briquets. 
Certain  coals,  like  the  Loydell  coal,  produce  a  fine  scale  of  coke 
in  burning  which  is  often  loosened  from  the  surface  of  the 
briquet  by  the  action  of  the  draft  and  carried  partially  burnt 
through  the  stack.  With  Hartshorne  and  Arkansas  coals  the 
coking  is  much  different  in  character,  probably  due  to  the 
higher  ash  content,  and  these  coke  scales  are  scarcely  notice- 
able. The  same  difference  was  noticed  in  burning  briquets 
made  from  Pocahontas  coal  and  "bone  coal"  picked  from  the 
mine  run  coal.  The  latter  was  high  in  ash  and  the  scales  were 
greatly  reduced. 

The  results  at  Altoona  -show  no  appreciable  reduction  in 


THE    ARMOUR     ENGINEER  [Jan.,  1911 

Fig.    20.      Burning    briquets    made    from    Pocahontas    coal    on    tugboat    running 
under  full  speed  in  harbor  at   Norfolk.      Photograph  taken  at  time  of  firing. 

Fig.  21.  Another  view  of  tug  shown  in  Fig.  20  burning  Pocahontas  coal, 
under  similar  conditions.  Photographs  were  taken  every  15  seconds  for 
five  minutes  to  cover  a  "firing  period,"  and  these  photographs  illustrate 
the    densest    smoke    observed. 

Vol.  Ill,  No.  11     BRIQUETTED  COAL:  MALCOLMSON  35 

the  weight  of  cinders  from  briquets,  but  a  decided  reduction  in 
their  calorific  value. 

During  December,  1907.  a  test  of  briquets  was  made  on  the 
TJ.  S.  S.  Connecticut  between  Xew  York  and  Hampton  Roads. 
The  results  were  so  encouraging'  that  more  briquets  were  or- 
dered by  the  Navy  Department  for  test  during  the  trip  of  the 
fleet  around  the  world.  Figs.  22  and  23  are  from  photographs 
taken  by  the  writer  as  the  ships  passed  out  the  Capes  and  illus- 
trate the  relative  smoke  producing  qualities  of  raw  and 
briquetted  coal.  Various  samples  of  Pocahontas  and  New 
River  coals  were  briquetted  and  tested  for  burning  qualities 
on  tug  boats  in  Hampton  Roads.  The  boilers  were  fired  at 
intervals  of  five  minutes,  known  as  "firing  periods,"  and  as 
nearly  as  possible  the  same  furnace  conditions  and  service 
were  maintained  throughout  the  test.  Photographs  were  taken 
every  fifteen  seconds  covering  a  firing  period  and  one  series 
taken  an  hour  while  smoke  readings  were  taken  every  fifteen 
seconds  throughout  the  test.  Figs.  20  and  21  illustrate  the 
densest  smoke  observed  for  similar  tests  of  briquetted  and  raw 

The  work  of  the  fireman  is  reduced  by  the  use  of  briquets. 
Their  uniform  size  makes  the  handling  easier ;  it  is  easier  to 
keep  up  steam  and  only  necessary  to  fill  up  the  holes  in  the  fire 
without  leveling.  No  slicing  is  necessary  as  is  usual  with  east- 
ern coals.  The  comparative  absence  of  clinker,  when  briquets 
are  properly  fired,  is  a  big  advantage  in  forcing  the  boiler  for 
heavy  grades  or  higher  speed. 

Summary   of   Advantages   of   Briquetted   over    Raw    Coal. 

In  general  the  following  advantages  may  be  claimed  for 
briquets  made  from  bituminous  coal  over  the  same  coal  not 
briquetted : 

1.  Comparative  absence  of  smoke. 

2.  Uniformity  of  size  and  quality. 

3.  Less  loss  of  fuel  in  ash. 

4.  Increased  furnace  and  boiler  efficiency. 

5.  Reduced  consumption  of  fuel  per  ton  mile. 

6.  More  fuel  can  be  burned  per  square  foot  of  heating 

surface,  hence  greater  capacity. 

7.  Less  slack  in  handling  fuel. 

8.  Less  clinker  and  cinders. 

9.  Longer  life  of  grates. 

10.     Fires  can  be  kept  up  for  longer  period  without  clean- 



[Jan.,  1911 

Fleet   passing   out   the   Capes,   December   16,   1907.      U. 
Connecticut    burning    briquets. 

Fig.    23.      Remainder    of    fleet    burning   coal.      All    of   the    ships    were 
well   under  way  and  boilers   working  under  similar  conditions. 

Vol.  Ill,  No.  1]     BRIQUBTTBD  COAL:  MALCOLMSON 

11.  Less  cleaning  of  tubes. 

12.  Less  labor  in  firing,  hence 

13.  Greater  efficiency  of  fireman. 

14.  Less  draft  needed. 

15.  More  uniform  steam  pressure. 

16.  Steam  pressure  can  be  increased  more  rapidly. 

17.  No  liability  to  spontaneous  combustion. 

18.  Availability  for  storage  without  deterioration. 


BY    B.   B.   FREUD.* 

Hydrogen  and  oxygen  can  exist  side  by  side  in  the  same 
containing  vessel  without  any  perceptible  combination  or  re- 
action taking  place.  Introducing  a  bit  of  platinum,  in  the 
proper  state  of  division,  into  such  a  mixture,  however,  causes 
an  immediate  reaction,  an  explosively  violent  one.  Such  a 
reaction  is  a  catalytic  one.  The  platinum  is  termed  the  cataly- 

On  considering  the  illustration  just  given,  it  is  seen  that 
thus  increasing  the  speed  of  a  chemical  action  requires,  ap- 
parently, the  expenditure  of  no  energy  whatever.  The  em- 
ployment of  the  platinum  adds  nothing  to  the  energy  the  hy- 
drogen and  oxygen  originally  possessed.  The  platinum  itself 
is  .recovered,  without  being  in  any  way  altered,  in  its  entirety 
and  is  just  as  efficient  after  the  action  as  before.  Theoretically, 
the  use  of  the  platinum  costs  nothing.  The  increased  speed  in 
the  reaction  of  the  hydrogen  and  the  oxygen  is  obtained  with- 
out cost.  In  this  connection  Ostwald  says,  "When  we  consider 
that  the  acceleration  of  a  reaction  by  catalysis  is  achieved 
without  consumption  of  energy,  and  so  proceeds  in  this  sense 
gratis,  and  that  in  chemical  industry  as  in  all  other,  time  is 
money,  we  perceive  that  the  systematic  utilization  of  catalytic 
appliances  is  likely  to  lead  to  the  most  thorough  going  changes 
in  manufacturing  processes." 

The  phenomenon  of  catalysis  was  first  recognized  as  such 
by  Berzelius  in  1835.  The  role  of  the  sulphuric  acid  in  the 
formation  of  ether  from  alcohol,  the  action  of  dilute  acids  and 
of  malt  extract  on  starch,  the  decomposition  of  hydrogen  perox- 
ide under  the  influence  of  metals  and  oxides,  the  action  of  fine- 
ly divided  platinum  in  mixtures  of  certain  gases,  all  led  him  to 
the  conclusion  "that  substances  by  their  mere  presence  and  not 
by  their  affinity  have  the  power  to  rouse  latent  affinities  so  that 
compound  substances  undergo  reaction  and  a  greater  electro- 
chemical neutralization   occurs."     And  this   conclusion,   after 

|In  the  preparation  of  this  report,  free  use  has  been  made  of  Smith's  General 
Inorganic  Chemistry ;  the  chapter  on  Catalysis  in  Duncan's  Chemistry  of 
Commerce;  Ostwald's  article  on  Catalysis  in  Nature,  Vol.  65;  Stieglitz' 
article  in  the  Congress  of  Arts  and  Science.  St.  Louis,  1904,  Vol.  IV,  and 
Stieglitz'  various  articles  in  the  American  Chemical  Journal,  1008,  et  seq. 
To   all    of  these   due   acknowledgment   is   made. 

•Associate  Professor  of  Analytical  and  Organic  Chemistry,  Armour  Institute 
of  Technology. 

Vol.  III.  No.  1]  CATALYSIS:      FREUD 

making  allowances  for  the  development  of  the  science  since 
1835.  is  correct  in  the  light  of  present  knowledge. 

Tt  must  not  he  supposed  that  catalytic  reactions  and  cata- 
lytic suhstances  are  uncommon.  Quite  the  contrary  is  the  case. 
In  fact  there  seems  to  he  no  kind  of  chemical  renction  which 
cannot  he  catalytically  influenced  and  no  chemical  suhstances. 
whether  elements  or  compounds,  which  cannot  act  catalytically. 
It  must  not  be  supposed,  however,  that  a  catalyst  can  he  found 
to  inaugurate  any  possible  chemical  change.  No  reactions  are 
possible  under  the  influence  of  catalysts  that  could  not  take 
place  in  their  absence  without  a  breach  of  one  of  the  laws  of 
energy.  The  original  change  may  proceed,  no  doubt,  very 
slowly,  as  in  the  action  of  hydrogen  and  oxygen  mentioned  in 
the  first  paragraph  of  this  paper.  So  slowly  may  this  change 
proceed,  that  without  careful  quantitative  measurement  spe- 
cially directed  to  the  point  no  change  at  all  can  be  observed. 
The  laws  of  energy  demand  that  the  reaction  must  take  place 
without  the  presence  of  the  catalyser.  They  prescribe  no  nu- 
merical value  to  the  velocity  of  the  change,  they  prescribe  only 
that  it  shall  not  be  zero,  that  it  shall  have  some  finite  value, 
however  small. 

Since,  then,  any  chemical  action  that  can  take  place  at  all 
can  be  catalytically  influenced,  this  influence  must  have  vast 
consequence  in  technical  application.  And  before  taking  up 
further  our  inquiry  into  the  nature  and  cause  of  catalysis.  I 
will  mention  some  of  the  technical  applications  of  the  phenom- 
enon. All  of  the  ferments  and  enzymes  are  catalysts.  Hence 
all  of  the  fermentation  industries  are  catalytic  in  their  nature. 
Chlorine  is  made  by  the  Deacon  process,  in  which  hydrochloric 
acid  is  oxidized  by  air  in  the  presence  of  copper  chloride,  the 
resulting  chlorine  being  used  in  various  substances  of  com- 
merce. Not  only  is  this  particular  application  of  catalysis  valu- 
able in  itself,  but  the  utilization  of  the  hydrochloric  acid,  a  by- 
product of  the  Le  Blanc  soda  process,  makes  it  the  more  valu- 
able because  thereby  it  saves  the  entire  Le  Blanc  process  from 
commercial  annihilation.  Another  catalytic  application  in  the 
soda  industry  is  the  Claus-Chance  process,  by  which  the  "tank 
waste"  is  used  as  a  source  of  hydrogen  sulphide,  which,  when 
mixed  with  air  is  passed  over  iron  oxide  and  changed  into  wa- 
ter and  the  commercially  valuable  sulphur.  The  manufacture 
of  'salt-cake"  by  the  Hargreaves-Robinson  process  is  also  a 
catalytic  application.  Here  sulphur  dioxide  and  air  react  with 
common  salt  in  the  presence  of  copper  chloride  and  the  valuable 
"salt-cake"  and  chlorine  are  produced.  The  greatest  of  all 
applications  of  catalysis  is  the  manufacture  of  sulphuric  acid 
by  the  "contact"  process.     Of  course  the  original  "chamber" 


THE    ARMOUR    ENGINEER  [Jan.,  1911 

process  is  also  a  catalytic  one,  but  the  newer  "contact"  pro- 
cess has  more  of  the  characteristics  of  a  catalytic  action  ap- 
parent in  it.  This  process  stands  as  one  of  the  greatest  achieve- 
ments of  industrial  application  of  the  catalytic  idea.  Another 
great  triumph  of  technical  chemistry,  the  synthesis  of  indigo, 
is  also  based  on  a  catalytic  action,  the  oxidation  of  naphthalene 
by  sulphuric  acid  in  the  presence  of  mercury.  It  may  be  men- 
tioned that  this  successful  preparation  of  indigo  on  a  commer- 
cial scale  has  resulted  in  an  agricultural  revolution  in  India. 
Then  there  is  the  oxidation  of  ammonia  to  nitric  acid  under  the 
influence  of  platinum  black,  and  the  oxidation  of  methyl  alcohol 
to  formaldehyde  and  "formalin"  under  the  influence  of  the 
same  agent.  Platinum  is  also  the  catalyst  in  one  of  the  re- 
actions in  the  synthesis  of  vanillin,  "artificial  vanilla."  Cop- 
per compounds  are  used  as  catalysts  in  the  manufacture  of 
various  dyes,  such  as  aniline  black  and  methyl  violet.  Man- 
ganese and  lead  compounds  used  as  "dryers"  in  the  oxidation 
of  linseed  oil,  act  catalytically.  Iodine,  in  the  manufacture  of 
that  universal  organic  solvent,  carbon  tetrachloride ;  barium 
carbonate,  in  the  manufacture  of  acetone  from  acetic  acid; 
nickel,  in  the  manufacture  of  stearic  from  oleic  acid;  lime,  in 
the  metallurgy  of  lead;  zinc,  in  the  manufacture  of  aldehyde 
from  alcohol;  these  all  are  technical  applications  of  the  phe- 
nomenon of  catalysis. 

Thus  we  see  what  a  catalyst  can  do.  How  it  accomplishes 
these  remarkable  results,  the  mechanism  of  its  action,  this  has 
been  the  inspiration  of  many  hypothetical  assumptions,  which 
did  little  service  other  than  to  delay  experimental  work  and  so 
postpone  a  scientific  explanation  of  the  phenomenon.  In  recent 
years  much  experimental  evidence,  particularly  of  a  quantita- 
tive nature,  has  been  obtained.  This  of  course  is  vital  to  a  sci- 
entific explanation  of  the  nature  and  mechanism  of  the  phe- 
nomenon. And  since  we  have  seen  that  the  applications  of 
catalysis  in  the  industries  are  so  important  and  so  extensive, 
whatever  will  be  discovered  in  regard  to  the  nature  of  catalysis 
will  find  immediate  applications  in  the  industries.  Hence,  I 
may  say  with  Ostwald  that  the  subject  has  not  only  a  chemical 
interest,  but  that  the  scientific  knowledge  and  investigation  of 
catalysis  must  have  vast  consequences  in  technical  application. 

To  recall  the  specific  problem  to  our  minds,  let  us  examine 
the  example  given  in  the  first  paragraph.  It  will  be  remem- 
bered that  the  hydrogen  and  the  oxygen  both  remained  peace- 
fully inactive  in  each  others'  presence  so  far  as  we  could  see. 
On  introducing  the  platinum,  however,  the  two  gases  immedi- 
ately and  explosively  reacted.  It  is  evident  that  the  addition 
of  the  catalyzer  cannot  add  to  the  intrinsic  energy  contained  in 

Vol.  Ill,  No.  11  CATALYSIS:      FREUD  41 

the  original  substances,  and  therefore,  it  cannot  increase  their 
intrinsic  energies  to  unite.  It  increases  the  speed  of  the  reac- 
tion merely.  The  platinum  itself  is  recovered  unchanged,  and 
as  efficient  as  ever.  How  this  increase  in  speed  is  effected,  that 
is  the  problem.  Of  course  the  "increase  in  speed"  is  to  be 
taken  in  a  negative  as  well  as  in  a  positive  sense.  For  while 
by  far  the  greater  percentage  of  catalytic  reactions  show  a  tre- 
mendously increased  velocity,  nevertheless  a  few  reactions  are 
on  record  which  are  catalytically  retarded. 

It  may  be  that  there  is  no  general  answer  to  the  question, 
why  and  how  catalyzers  exert  their  marvelous  accelerating  in- 
fluences. Such  a  generalization  would  be  possible  only  after  a 
study  of  a  large  number  of  individual  cases.  One  of  the  most 
important  contributions  to  the  subject  has  been  made  by  Stieg- 
litz  and  his  co-workers,  whose  experimental  evidence  shows 
exactly  how  the  particular  catalyzers  in  the  particular  reactions 
they  studied,  accomplish  their  results.  And  there  is  no  doubt 
but  that  the  conclusions  of  Stieglitz  in  this  study  can  be  very 
largely  generalized.  In  the  endeavor  to  answer  the  question 
as  to  how  and  why  a  catalyzer  works,  he  studied  the  catalysis 
of  methyl  acetate  under  the  influence  of  water  and  acids.  The 
following  are  the  facts.  The  saponification  of  methyl  acetate 
by  water  proceeds  very  slowly,  according  to  the  following 
equation : 

CHsCOOCH3  -f  H20  ->  CH,COOH  +  CH3OH.        (1) 

Acids  greatly  accelerate  the  saponification  proportionately  to 
the  concentration  of  the  hydrogen  ion  used.  It  has  been 
shown,  also,  that  the  final  condition  of  equilibrium  of  the 
reversible  reaction, 

CH3COOH  +  CTI,OH  -»  CH3COOCH3  +  H=0,        (2) 

is  not  appreciably  altered  by  the  catalyzer.  In  other  words, 
that  the  acid  accelerates  the  velocity  in  either  direction  to  the 
same  extent.  It  has  also  been  shown  that  the  catalyzer,  the 
acid  or  hydrogen  ion,  appears  to  act  by  its  presence,  simply; 
that  it  appears  to  remain  unchanged  throughout  the  course  of 
the  reaction.  These  three  properties  have  been  assumed  to  be 
typical  of  all  catalytic  actions. 

Stieglitz  took  the  first  vital  and  decisive  step  when  he  de- 
parted from  the  old  idea  that  catalytic  action  may  be  studied 
only  in  reactions  which  complied  with  these  three  fundamental 
principles,  which  for  emphasis  I  will  repeat;  first,  that  the  ac- 

42  THE    ARMOUR    ENGINEER  [Jan.,  1911 

celeration  is  proportional  to  the  concentration  of  the  catalytic 
agent ;  second,  that  the  condition  of  equilibrium  in  a  reversible 
reaction  must  not  be  measurably  changed  by  the  presence  of  the 
catalytic  agent ;  and  third,  that  the  catalytic  agent  must  appear 
to  act  by  its  presence  simply,  and  not  to  form  a  compound  in 
quantity  with  any  other  components.  These  three  properties 
have,  in  the  past,  been  assumed  to  be  necessary  and  typical  of 
catalytic  action,  but,  in  this  study,  the  vital  fact  of  acceleration 
(in  a  positive  or  negative  sense),  alone  was  considered  charac- 

In  regard  to  the  acceleration  of  the  velocity  of  saponifica- 
tion of  methyl  acetate  (equation  No.  1)  by  acids,  the  most  fun- 
damental fact  concerning  acids,  namely,  their  ability  to  form 
salts  with  bases  and  oxides,  suggested  itself.  The  logical  con- 
clusion was  that  the  methyl  acetate  has  basic  properties,  and 
the  salt  formation  with  acids  is  intimately  connected  with,  if 
not  the  cause  of,  the  catalysis.  Of  course,  the  basic  properties 
of  methyl  acetate  must  be  far  too  weak  to  permit  of  quantita- 
tive measurement  of  its  constants,  so  the  class  of  closely  related 
bodies,  the  imido  esters,  whose  quantitative  measurement  of  all 
necessary  factors  could  be  had,  were  studied.  The  imido  esters 
are  esters  in  which  the  imide  group  (=N — H)  replaces  the  oxy- 
gen atom  of  the  ester,  as  in  imido  methyl  acetate  CH3C(=NH) 
OCH3.  These  are  distinctly  basic  substances  which  form  well 
defined  salts.  The  free  bases  are  very  slowly  decomposed  by 
water,  chiefly  according  to 

CeH5C  (=NH)  OCH3+H20  ->  C,,H5CONH2+CH3OH    (3) 

and  yet  more  slowly  according  to 

C6H5C  (=NH)  OCII3+H20  -^  C0Hr,COOCH3+NH3,       (4) 

both  reactions  being  practically  non-reversible.  The  addition 
of  hydrochloric  acid  greatly  increases  the  velocity  of  the  second 
reaction  (equation  No.  4),  which  becomes  almost  the  exclusive 
one.  How  does  the  acid  accelerate  the  reaction?  That  is  the 
question.  The  acid  forms  the  hydrochloride,  but  as  the  imido 
esters  are  weak  bases,  partial  hydrolysis  takes  place  and  a  con- 
dition of  equilibrium  results,  thus 

C6H5C  (NH2C1)  OCH3  :  H20->C6H5C  (NH2OH)  OCH3  •  IIC1  (5) 

The  reaction  presents,  therefore,  at  least  three  possibilities, 
the  velocity  may  be  proportionate  to  the  concentration  at  any  CATALYSIS:      FREUD  43 

moment  of  the  salt,  to  that  of  the  free  base,  or  to  the  total  sub- 



=  Ksalt   •  (salt), 


=  Kbase   •  (base), 



=  Ksllhstanc.e    •   (substance). 



In  order  to  decide  between  these  three,  it  was  necessary  to  de- 
termine experimentally  the  actual  change  (X)  in  time  (t),  and 
also  the  proportions  of  salt,  free  base,  and  acid  present  at  any 
moment  (t).  This  latter  is  determined  according  to  Arrhenius' 
e< [nation  for  the  solution  of  a  hydrolyzed  salt 

Positive  ion  Kbase 

= ==  Khydrolysls,  (0) 

base  •  H  KwatPr 

The  constant  K  was  determined  by  conductivity  measurements. 
and  with  its  aid  the  concentrations  of  salt.  base,  and  acid  for 
the  differential  equations  (6,  7.  and  8)  were  calculated.  The 
results  show  that  the  true  course  of  the  reaction  is  given  by 
equation  (6).  which  alone  leads  to  a  true  constant.  It  is  there- 
fore certain  that  hydrochloric  acid  which  enormously  increases 
the  velocity  of  saponification  of  the  imido  ester  according  to 
equation  (4),  does  so  simply  and  quantitatively  on  account  of 
salt  formation. 

The  accelerating  or  catalytic  action  of  the  acid  is  here 
surely  due  then  to  salt  or  ion  formation  of  a  different,  less  sta- 
ble, more  reactive  molecule. 

This  increase  in  the  velocity  of  a  chemical  action  is  the 
main  characteristic  of  the  phenomenon  of  catalysis,  and  we 
have  seen  a  simple  explanation  of  it  based  on  rigorous  experi- 
mental proof.  Now  it  remained  to  ascertain  whether  the  two 
other  important  characteristics  for  many  catalytic  reactions, 
namely;  the  fact  that  the  catalyzing  agent  need  not  appear  to 
combine  with  anv  of  the  reacting  substances,  and  the  fact  that 

44  THE    ARMOUR    ENGINEER  [Jan.,  1911 

in  a  reversible  reaction  it  need  not  measurably  change  the  final 
condition  of  equilibrium,  are  also  in  agreement  with  this  con- 
ception of  the  course  of  a  catalytic  reaction. 

The  following  experimental  evidence  shows  why  the  cata- 
lyzing acid  need  not  appear  to  combine  with  any  of  the  react- 
ing substances.  It  was  shown  that  the  saponification  of  imido 
esters  takes  place  according  to 


=  Ksalt   ■  (salt),  (6) 


According  to  Arrhenius  and  Walker 

(salt)  =K  •  (base)    •  (H),  (10) 



=  K'   •  (base)    •  (H).  (11) 


Now  this  is  exactly  the  velocity  for  ester  catalysis,  substituting 
"(ester)"  for  "(base)."  This  shows  the  connection  between 
the  catalysis  of  the  imido  esters  and  that  of  the  ordinary  esters. 
For  if  the  latter  could  be  considered  to  be  a  base,  and  could 
form  salts,  its  saponification  could  undoubtedly  be  due  to  the 
saponification  only  of  its  salt  or  positive  ion.  This  link  in  the 
proof  was  supplied  by  Baeyer,  who  showed  that  esters  form 
well  defined  salts  (oxonium  or  quadrivalent  oxygen  salts)  with 
acids,  very  unstable  ones,  but  nevertheless  salts:  and  Coehn 
proved  that  they  are  electrolytes.  According  to  this  idea  we 
can  write  for  the  reaction, 

CH3COOCH3  +  H20  ->  CH3COOH  +  CH3OH        (1) 

the  following: 


—  Kgap0nincation  ■  (positive  ester  ion)   •  H.,0    (12) 


as  was  proved  experimentally  for  the  imido  esters. 

Vol.  Ill,  No.  1]  CATALYSIS:      FREUD  45 

For  the  combination  of  methyl  acetate  with  water  to  form 
an  oxonium  base  and  for  its  ionization,  we  have, 

OH  +  — 

CH3COOCH3+H20  *±  CH3COOCH3  ?=>  CH3COOCH3+OH,  (13) 
H  H 



(Positive  ester  ion)  = •  (ester)  •  (II)  (14) 


Substituting  in  equation   (12)    we  have  for  the  saponification 
of  methyl  acetate  by  water, 

Velocity  of  saponification 



(ester)   •  (H)   •  (H20).      (15) 

If  we  saponify  with  hydrochloric  acid  the  reaction  similarly 
will  lie, 

CH3COOCH3  +  HC1  <=± 


CH3COOCH3  +  H20  <=*  CH3COOCH3  +  HC1    (16) 
H  H 

According  to  Arrhenras,  the  equation  for  hydrolyzed  solutions 
of  salts  of  weak  bases  with  strong  acids,  is 


Positive  ester  ion  = ■  (ester  — y)   •  (H').   (17) 


For  an  almost  completely  hydrolyzed  salt  "y"  is  negligible. 

46  THE    ARMOUR    ENGINEER  [Jan.,  1911 

Hence  the  velocity  of  saponification  of  methyl  acetate  in  the 
presence  of  hydrochloric  acid  becomes 


•  (ester)    •  (H')    ■  (H.,0)   (18) 


Comparing  the  two  velocity  equations  (18  and  15)  for  the 
saponification  in  the  presence  of  water  alone,  and  in  the  pres- 
ence of  acid,  it  is  seen  that  the  velocity  must  in  fact  increase 
directly  proportionate  to  the  concentration  of  the  hydrogen  ion, 
since  all  other  factors  remain  constant.  Hence  the  experi- 
mental results  do  not  dispute  the  consequences  of  the  theory. 
And  now,  the  last  important  fact,  namely,  that  in  a  reversi- 
ble reaction,  the  catalyzer  need  not  measurably  change  the 
final  condition  of  equilibrium.  The  saponification  of  methyl- 
acetate  is  a  reversible  reaction. 

CH3COOH  +  CH3OH  ->  CH3C00CH3  +  H20        (19) 

The  velocity  of  this  reaction  is  also  accelerated  by  the  addition 
of  hydrochloric  acid.  This  increased  velocity  under  the  influ- 
ence of  an  acid  must  be  due  to  minimal  basic  properties  of 
acetic  acid,  or  methyl  alcohol.  Surprising  as  it  may  seem,  it  is 
to  the  basic  properties  of  acetic  acid  that  we  must  look  in  this 
instance.  Other  workers,  Rosenheim  and  Euler,  have  shown 
that  acetic  acid  must  form  oxonium  salts  and  have  some  basic 
functions.  Applying  this  conception  to  the  study  of  the  veloc- 
ity of  esterification,  the  velocity  in  the  absence  of  water  is, 

Vesterification  =  Kest  '  (pos.  acetate  ion)    •  (CH3OH),  (20) 

K  base 

=  Kest  • •  (acetic  acid^   •  (H)   •  (CH3OH).  (21) 


In  the  presence  of  acid,  the  equation  becomes, 


Vest  .  hci  =  Kebt  -  -      ""  —  ■  (acetic  acid)  •  (H')  •  (CH3OH).(22) 

The  change  in  the  velocity  of  esterification  is  seen  to  be  pro- 
portionate to  the  change  in  concentration  of  the  hydrogen 
ion.     This  is  in  accord  with  the  theory  proposed,  and  is  with 

Vol.  Ill,  No.  11  CATALYSIS:      FREUD  47 

the  experimental  parts.     When  equilibrium  is  established,  in 
absence  of  acid, 

"saponification   *eSterif  icat  ion;   Or  \^) 


Ksap  •—     -  ■  (ester)   •  (H20)   ■  (H)  = 

-ft-  base 

Kest- •  (acetic  acid)  •  (CII3OII)  ■  (H)  (24) 


and  m  the  presence  of  acid, 

*  saponification  HC1  *  esterif  icat  ion  HC1,  OF  {^) 


Ksap  •  -    —  •  (ester)    •  (H')    •  (H.O)  = 

Kest  : —  ■  (acetic  acid)  •  (CH3OH)  •  (H')    (26) 


In  other  words  the  addition  of  the  catalyzing  acid  will  not 
effect  the  ultimate  condition  of  equilibrium  between  the  com- 
ponents of  the  reaction. 

In  accordance  with  these  results  of  Stieglitz,  and  his  co- 
workers, our  views  concerning  catalytic  action  must  be  modi- 
fied in  regard  to  all  three  of  the  commonly  assumed  funda- 
mental characteristics  of  catalytic  action.  These  three  charac- 
teristics are  practically  true  only  for  limiting  cases,  where  the 
amount  of  salt  formation  is  too  small  to  measure.  None  of 
them  are  absolutely  true  under  any  condition. 

The  one  vital  fact,  OF  AN  ACCELERATION  DUE  TO  AN 
is  the  ONLY  fundamental  fact  common  to  ALL  catalytic  action. 

BY  C.  E.  BECK.* 

Up  to  about  ten  years  ago  little  was  known  in  the  United 
States  about  gas  calorimetry  and  its  commercial  possibilities. 
A  number  of  the  technical  institutions  had  gas  calorimeters, 
as  did  also  several  of  the  large  gas  manufacturing  companies, 
but  its  use  by  the  latter  was  not  intended  to  be  of  any  great 
commercial  value.  As  a  matter  of  fact  there  was  no  object  in 
knowing  the  heating  value  of  a  gas,  because  a  candle-power 
criterion  was  the  acknowledged  standard  and  a  gas  having  the 
required  illuminating  qualities  usually  ran  high  enough  in  heat 
value  to  cope  with  all  practical  requirements.  In  Germany, 
however,  greater  stress  had  been  laid  upon  the  thermal  quali- 
ties of  a  gas,  it,  perhaps,  being  due  to  their  more  advanced 
commercial  means  of  using  gas.  It  is  very  evident  that  Ger- 
many is  without  a  peer  as  regards  the  development  of  the  in- 
ternal combustion  engine,  and  from  this  it  is  natural  to  assume 
that  she  is  not  inferior  to  anyone  in  gas  manufacturing..  Things 
progressed  rather  slowly  in  the  United  States  until  the  gas 
engine  manifested  its  commercial  possibilities.  The  gas  calori- 
meter at  once  fell  into  demand  as  gas  engine  manufacturers 
were  incited  to  make  guarantees  based  on  the  heat  value  of  the 
gas  to  be  used  in  their  engines.  It  was  entirely  a  matter  of 
heat  value  that  regulated  the  rating  of  internal  combustion 
engines,  and  with  a  few  exceptions  gas  constituents  were  not 

It  is  now  estimated  that  about  90%  of  all  the  gas  manu- 
factured is  used  for  power,  heating  and  incandescent  lighting, 
and  it  is  very  evident  that  these  three  factors  depend  entirely 
upon  heat  value  for  their  output.  With  this  in  view  the  civic 
authorities  in  some  of  our  states  enacted  laws  whereby  all  gas 
companies  having  a  certain  minimum  output  of  gas  per  year 
were  compelled  to  maintain  a  given  standard  heat  value  of 
their  gas.  Wisconsin  was  the  first  state  to  enact  these  meas- 
ures, being  followed  by  New  York  and  quite  a  number  of 
other  large  cities.  Consequently,  gas  calorimetry  as  well  as 
the  gas  calorimeter  now  received  quite  an  impetus,  but  the 
question  that  troubled  the  minds  of  authorities  was  what 
calorimeter  would  be  the  most  satisfactory  to  use.  As  a  result 
the  American  Gas  Institute  appointed  a  committee  on  calori- 
metry to  investigate  and  conduct  exhaustive  tests  on  all  avail- 
able instruments. 

♦Class    of    1911,    Armour    Institute    of    Technology.      Manager,    Sargent    Steam 
Meter  Co.,    Chicago. 

Vol.  Ill,  No.  1] 



Gas  calorimetry  may  be  defined  as  the  quantity  of  heat 
generated  by  the  complete  combustion  of  a  unit  volume  of  gas. 
The  apparatus  used  to  determine  this  quantity  is  called  a 
"Calorimeter,"  which  when  complete  consists  of  a  calorimeter 
proper,  a  gas  meter,  governor,  thermometers,  weighing  buckets 

Jankers     Calorimeter.      Sectional   Views   and   Elevation. 

and  scales.  In  this  article  only  the  water  heater  type  of  in- 
strument will  be  dwelt  upon,  as  it  has  proven  to  be  the  most 
satisfactory.  In  its  performance  the  heat  generated  by  the 
complete  combustion  of  a  unit  quantity  of  gas  is  absorbed  by 
a  given  weight  of  water,  thereby  causing  a  rise  in  tempera- 
ture. The  unit  in  which  this  heat  is  measured  is  called  a  British 
Thermal  Unit  in  the  English  system,   and  is   defined  as  the 



[Jan.,  1911 

quantity  of  heat  required  to  raise  the  temperature  of  one  pound 
of  water  one  degree  Fahrenheit  at  62°  F. 

There  are  but  four  gas  calorimeters  manufactured  that  are 
worthy  of  mention,  and  only  two  of  these  have  wide  applica- 
tion in  commercial  practice.  The  first  instrument  to  be  described 
is  the  Junkers,  a  sectional  and  external  elevation  of  which  is 

Fig.    2.      Sargent    Automatic    Gas    Calorimeter.      Sectional    Elevation. 

shown  in  Fig.  1.  This  instrument  was  designed  by  Hugo 
Junkers  of  Germany,  and  is  perhaps  the  best  known  instru- 
ment of  its  kind,  although  it  is  being  supplanted  by  the  Sar- 
gent, an  American  made  instrument,  to  be  described  later. 

In  Fig.  1,  water  at  approximately  room  temperature  enters 

Vol.  Ill,  No.  11 



the  weir  "A,"  flowing  down  the  inlet  pipe  "B"  to  the  thermom- 
eter at  "  C, "  where  the  temperature  is  taken.  A  quadrant  valve 
"D"  is  used  to  regulate  the  rate  of  flow.  The  water  on  enter- 
ing the  instrument  flows  upward  against  the  direction  of  flow 
of  the  products  of  combustion,  which  come  down  through  the 
thin  copper  tubes  "E,"  being  discharged  at  room  temperature 

through  the  flue  "J,"  where  a  damper  regulates  the  velocity 
of  discharge.  Combustion  of  the  gas  takes  place  at  "K, "  a 
Bunsen  burner  being  used  for  the  purpose.  The  water  passing 
upward  absorbs  the  sensible  heat  liberated  by  the  products  of 
combustion  as  well  as  the  latent  heat  given  up  by  the  conden- 



[Jan.,  1911 

sation  formed  in  the  combustion  of  hydrogen  and  other  hydro- 
carbons. At  "I"  a  series  of  baffle  plates  thoroughly  mix  the 
water,  which,  after  passing  over  the  outlet  thermometer  "G," 
where  the  outlet  temperature  is  taken,  is  discharged  through 
the  weir  "H."  About  the  only  criticism  to  be  offered  on  this 
instrument  is  that  the  inlet  and  outlet  thermometers  not  being 
on  the  same  level  make  it  a  tiresome  operation  for  an  observer 
to  perform  continuous  runs. 

Fig.  4.     Complete  Apparatus  for  Gas  Calorimetry. 

The  Sargent  Automatic  Gas  Calorimeter,  section  elevation 
of  which  is  shown  in  Fig.  2,  was  designed  by  C.  E.  Sargent 
of  Chicago,  who,  through  his  experience  with  internal  com- 
bustion engines,  realized  the  application  and  value  of  a  gas  cal- 
orimeter in  commercial  practice.  The  Sargent  instrument,  since 
its  inception,  has  been  built  in  several  different  models,  each 
one  better  than  the  preceding.  In  the  figure  is  shown  the  latest 
model  which  is  now  recognized  as  a  standard  and  which  em- 
bodies all  the  suggestions  set  forth  by  the  Committee  on  Gas 
Calorimetry  of  the  American  Gas  Institute.  In  construction  the 
Sargent  instrument  does  not  differ  widely  from  the  Junkers. 
The  inlet  and  outlet  thermometers  are  on  the  same  level  and 
the  device  is  equipped  with  an   electrical  automatic   attach- 

Vol.  Ill,  No.  1] 



ment  so  that  at  each  revolution  of  the  gas  meter  needle,  the 
discharge  water  is  automatically  switched  from  one  receptacle 
to  another.  By  this  means  continuous  operations  can  be 
performed  and  the  personal  error  in  switching  a  hose  elim- 
inated. The  efficiency  of  the  calorimeter  is  about  99.5%.  As 
a  complete  outfit  the  Sargent  apparatus  is  recommended  be- 

Fig.    5.      Boys     Calorimeter.      Sectional    View. 

cause  the  heat  value  of  a  gas  is  computed  in  English  units 
direct,  by  the  use  of  Fahrenheit  thermometers  and  decimal 
scales  which  weigh  the  discharge  water  to  .01  of  a  pound. 
The  gas  meter  measures  1/10  of  a  cubic  foot  per  revolution 
and  with  its  integrating  train  has  a  range  of  from  .001  to 
100  cubic  feet.  The  meter  is  equipped  with  a  single  "which- 
way"  level,  has  three  leveling  screws,  a  drain,  filler,  ther- 
mometer and  a  U-gauge.  The  entire  outfit  is  made  of  brass 
and  copper.  Fig.  3  is  a  cut  of  the  meter  and  Fig.  4  the  com- 
plete apparatus. 



[Jan..  1911 

The  Boys  Calorimeter,  shown  in  Fig.  5,  was  designed  by 
C.  V.  Boys  of  London,  England,  and  has  been  adopted  by  the 
London  Referees  for  determining  the  heat  value  of  London  gas. 
This  instrument  is  not  very  satisfactory  on  account  of  the 
whole  body  having  to  be  removed  to  light  the  burner  "B."  '  It 
also  has  a  burner  that  produces  a  luminous  flame,  and  when 
burning  a   gas  containing  a   considerable   quantity  of  hydro- 

rig.  6.     Simmance-Abady   Calorimeter.     Sectional   View. 

carbon,  a  carbon  deposit  is  effected,  indicating  incomplete  com- 
bustion. It  will  be  noted  that  the  products  of  combustion  pass 
up  a  central  flue  and  then  down  and  up  over  a  coil  provided 
with  considerable  heating  surface,  and  through  which  the 
water  passes. 

The  Simmance-Abady  Calorimeter,  shown  in  Fig.  6,  is 
another  English  instrument,  and  differs  in  construction  from 
any  yet  shown.     The  water  and  products  of  combustion  pass 

Vol.  Ill,  No.  1]  GAS    CALORIMETRY:      BECK  55 

up  and  down  through  a  series  of  annular  chambers.  The  device 
is  lagged  with  wood,  which  has  been  found  inferior  to  a  metal 
jacket,  and  the  outlet  thermometer  comes  in  direct  contact 
with  irregularly  heated  water,  which  is  not  churned  by  baffle 
plates  and  which  causes  wide  variations  in  the  outlet  tempera- 
tures. The  annular  chambers  and  their  connections  cause  air 
trapping,  and  at  times  a  very  irregular  flow  of  water.  The 
excessive  weight  of  the  Simmance-Abady  also  renders  it  im- 
possible to  detect  slight  changes  in  the  heat  value  of  a  gas  on 
account  of  the  heat  inertia  set  up  by  the  excess  metal. 

As  a  standard  the  Boys  and  the  Simmance-Abady  instru- 
ments are  not  considered  in  the  United  States.  The  Sargent 
and  the  Junkers  are  recommended,  there  being  about  150  of 
the  former  now  in  use,  with  the  demand  rapidly  increasing. 

Of  course,  there  are  many  things  about  gas  calorimetry  and 
the  design  of  a  gas  calorimeter  that  have  not  been  mentioned 
in  this  article.  Take  for  instance  the  effect  of  using  water  be- 
low and  above  room  temperature,  the  effect  of  humidity,  rate 
of  combustion  and  of  varying  the  temperature  of  the  discharge 
products  of  combustion.  All  of  these  factors  are  responsible 
for  the  errors  manifested  in  commercial  results,  but  as  their 
combined  effect  under  the  most  unfavorable  conditions  does  not 
cause  excessive  errors,  corrections  are  usually  neglected.  In 
calorimeter  design  it  is  advisable  to  use  light  material  in  order 
to  reduce  the  effect  of  heat  inertia  to  a  minimum.  The  water 
of  contents  should  be  as  small  as  possible  in  order  to  detect 
slight  changes  in  heat  value  quickly  and  accurately.  The  inlet 
and  outlet  thermometer,  should  have  no  heat  communication 
with  each  other,  the  outlet  water  must  be  thoroughly  mixed 
and  a  uniform  flow  should  be  maintained  by  the  use  of  weirs. 
By  all  means  a  metal  surrounded  air  jacket  is  always  advisable 
as  the  evaporation  of  water  spilled  on  a  wood  jacket  will  lower 
the  heat  value  of  the  gas  being  tested. 

The  above  suggestions  as  well  as  many  others  of  minor 
consideration  have  been  incorporated  in  the  Sargent  and  Junk- 
ers instruments,  and  when  we  consider  convenience  of  opera- 
tion, accuracy  and  efficiency,  these  instruments  have  no  equal. 


The  water  supply  for  old  Sidon,  a  town  of  some  10,000 
people  built  on  or  very  near  the  ruins  of  the  ancient  Phoenician 
city  of  the  same  name,  is  piped  about  two  miles  from  a  river 
flowing  by  the  city  on  the  north.  The  built-up  portion  rises 
gently  back  from  the  sea  to  perhaps  seventy-five  feet  above  sea 
level,  and  is  crowned  by  an  old  Crusader  castle,  which  over- 
looks the  city  and  the  surrounding  fields  and  gardens.  Distri- 
bution of  water  is  made  in  the  lower  town  from  a  standpipe 
which  will  send  water  to  an  elevation  of  about  sixty-five  feet ; 
so  that  the  upper  town  is  not  furnished  with  running  water. 
Rising  up  thru  the  center  of  the  stone  tower  is  the  main  pipe, 
which  overflows  inside  of  an  open  stone  basin  some  four  feet 
in  diameter.  Holes  in  the  rim  of  this  basin,  of  equal  size  and 
under  equal  head,  gauge  the  units  of  supply,  and  these  units 
are  sold  outright  at  the  tower  for  a  market  price,  just  as  land 
would  be.  From  here  an  owner  may  do  as  he  pleases  with  his 
supply — pipe  it  to  any  place  as  a  whole  or  in  part,  or  sell  any 
part  of  it. 

Such  a  system  of  course  involves  the  use  of  many  long 
strings  of  small  pipe  and  this  causes  the  principal  drawback 
to  its  use,  for  in  the  rainy  season  much  fine  silt  goes  the  full 
length  of  the  system,  finally  to  settle  in  the  small  pipes  and 
eventually  to  close  them.  Partly  to  avoid  this,  the  water  is 
cut  off  toward  the  end  of  the  dry  season  for  a  week  or  so,  while 
the  mains  are  cleaned,  and  at  such  times  the  people  have  to  use 
the  brackish  water  of  old  wells  under  the  houses  or  else  pack 
spring  water  in  jars  from  some  distance.  Of  course,  the  fact 
that  the  river  Water  is  largely  surface  drainage  adds  to  the 
danger  of  pollution,  but  modern  orientals  seem  to  have  paid 
less  attention  to  that,  until  very  recently,  than  even  the  an- 
cients did. 

Under  these  conditions  the  Americans  in  charge  of  the 
Mission  Schools  sank  two  drilled  wells  to  about  900  feet,  and 
the  water  in  them  rose  from  about  750  feet  below  sea  level 
to  20  feet  below  the  surface  of  the  school  yard,  which  is  there 
at  an  elevation  of  +50  feet.  This  was  in  1901,  and  for  some 
years  a  rather  unique  pumping  system  was  in  use.  The  first 
45  feet  was  drilled  thru  the  earth  filling  of  the  old  city  moat 
over  which  the  school  stands,  and  this  had  been  dug  out  around 
the  casing  down  to  an  elevation  of  +5.0  feet,  where  a  coarse 

•Class  of  1906,  Civil  Engineer,  Board  of  Local  Improvements,  City  of  Chicago. 

Vol.111,  No.  1]   ARTESIAN  WATER  IN  ORIENT  :    FORD 

brown  sandstone  that  underlies  the  whole  region  was  found. 
It  was  noticed  that  considerable  amounts  of  water,  which  over- 
flowed the  casing  during  drilling,  escaped  quite  freely  thru 
this  sandstone.  Using  this  fact,  the  idea  was  hit  upon  of  join- 
ing the  two  wells  (about  90  feet  apart)  with  the  drive  pipes  of 
two  hydraulic  rams,  these  pipes  taking  the  water  from  one 
well  and  delivering  it  to  the  rams  set  on  a  platform  in  the 
other  well,  this  well  receiving  the  overflow  from  the  waste 

For  a  long  while  the  porous  sandstone  carried  off  this 
waste,  but  finally  dust  and  dirt  sifted  in  to  such  an  extent  as 
to  clog  the  pores  so  that  the  larger  ram,  and  then  the  smaller 
one,  had  to  be  stopped.  This  was  no  small  hardship  to  both 
the  school  and  the  neighbors,  for  many  had  made  good  use 
of  the  little  stream  kept  flowing  outside  the  school  compound 
in  a  sort  of  public  fountain.  Hand  pumps  were  put  in,  but 
their  use  by  townspeople  during  school  hours  was  a  great  an- 
noyance, and  the  forcing  of  water  from  the  boys'  school,  where 
the  wells  were,  thru  the  town  some  thousand  or  eleven  hundred 
feet  to  the  girls'  school,  to  supply  about  one  hundred  people, 
was  a  tiresome  job. 

During  a  year  spent  in  1909-1910  assisting  in  various  proj- 
ects connected  with  the  schools  and  the  Industrial  Farm  be- 
longing to  them,  the  writer  helped  to  remedy  the  conditions 
outlined  above.  An  underground  pump  room  was  dug  out 
around  the  well,  walled  up,  and  arched  over  so  as  to  leave  the 
boys'  yard  undisturbed  except  for  an  entrance  way.  In  this 
was  installed  a  ten-inch  Rider-Ericsson  hot  air  engine,  chosen 
because  of  its  simple  build  and  action  as  perhaps  the  best 
adapted  to  such  a  distance  from  repair  facilities,  and  to  opera- 
tion by  a  native  workman.  A  system  of  distribution  pipes  and 
tanks  among  the  various  school  buildings  was  arranged,  not 
without  some  difficulty  owing  to  the  native  architecture,  for 

Sidon    as    Viewed    from  Seminary    Compound. 



[Jan.,  1911 

when  those  innumerable  corners  had  to  be  turned  and  the 
heavy  walls  pierced  for  such  modern  innovations  as  bath-room 
plumbing,  it  was  no  easy  matter.  However,  the  real  experience 
of  the  job,  amusing  enough  in  the  narration,  but  far.  from 
amusing  at  the  time,  was  the  tearing  up  of  the  old  piping 
between  the  two  schools  and  the  laying  of  new  and  larger 
pipe,  by  another  route. 

In  the  accompanying  sketch  of  a  typical  cross  section  of 
a  Sidon  street  can  be  seen  the  general  arrangement  of  paving, 
drains  and  sewers,  and  water  pipes  when  there  are  any.   It  may 


Typical     Cross 

The  F\rmo<it 
!•<•(  ion     of    Street. 

be  apparent  that,  except  for  crowding,  the  system  is  essentially 
that  in  any  ordinary  city,  but  it  was  this  crowding  which 
caused  all  our  troubles,  or  most  of  them.  One  of  the  old  lines 
was  of  1^4**  pipe  which  had  been  in  use  for  the  past  twenty-five 
years  to  carry  one-half  of  the  city  water  belonging  to  both 
schools  over  to  the  girls'  school.  It  was  found  about  three- 
fourths  full  of  fine  river  silt,  but,  considering  its  age,  not  badly 
corroded.  The  other,  a  1-inch  pipe  used  with  the  pump  and  ram 
for  artesian  water,  was  so  badly  eaten  on  the  inside  after  only 
eight  or  nine  years,  that  a  man's  little  finger  would  scarcely  en- 

Vol.  Ill,  No.  1]   ARTESIAN  WATER  IN  ORIENT:    FORD  59 

ter  the  end.  In  the  recent  purchase  of  some  property,  the  Mis- 
sion acquired  another  unit  of  city  water  for  use  at  the  girls' 
school,  and  this  was  fed  from  a  sort  of  sub-station  along  the  line 
of  our  work,  to  which  we  made  connections.  These  smaller 
standpipes  are  scattered  all  over  the  town  and  are  fed  from  the 
main  tower  in  larger  pipes  than  individuals  would  use,  thus 
saving  expense  and  friction,  both  of  which  facts  even  the 
oriental  has  found  out. 

For  the  supply  of  artesian  water  to  the  other  school  we 
used  a  lot  of  3-inch  pipe,  already  on  hand,  and  this  we  connect- 
ed to  the  discharge  main  from  the  air  engine.  Right  here  our 
troubles  began.  Often  we  came  to  some  old  house  drain  almost 
falling  to  pieces  and  built  so  high  that  between  the  cover  flags 
of  the  drain  and  the  paving  flags  there  was  no  room  for  the 
pipe ;  then  if  the  drain  fell  apart,  it  had  to  be  rebuilt.  At  some 
other  time  a  slight  bend  would  occur  in  a  narrow  part  of  the 
street,  too  small  to  use  any  angle  fitting  we  could  possibly  pro- 
cure, and  since  our  pipe  supply  was  limited,  and  even  standard 
fittings  were  scarce  articles,  we  were  forced  to  bend  our  pipes. 
A  pipe  sixteen  feet  long,  by  the  way,  with  a  bend  near  the 
fixed  end,  was  not  the  easiest  thing  in  the  world  to  connect  in 
cramped  quarters.  Add  to  this  the  fact  that  the  paver  was 
replacing  the  flags  only  two  or  three  joints  back,  so  as  to  keep 
as  little  of  the  street  open  as  possible,  and  that  every  lifting  of 
the  end  of  the  pipe  jarred  his  work  and  scraped  off  the  tar 
that  had  been  used  to  protect  the  pipes  as  the  only  means  of 
waterproofing  at  hand.  Then,  perhaps,  in  getting  over  or 
under  some  other  man's  line  of  pipe  we  either  broke  it  and  had 
to  stop  to  repair  it  or  else  we  worked  too  close  to  some  loose 
sewer  stones  and  broke  through  them  for  another  job  of  re- 

These  were  some  of  the  mechanical  difficulties,  but  what- 
ever fate  it  was  that  was  amusing  itself  at  our  expense,  it  had 
other  methods  than  these.  Imagine  the  streets  shown  in  the 
photographs  (the  weather  prevented  taking  shots  of  the  actual 
scene  of  the  work)  to  be  lined  with  the  little  eight-by-ten  shops 
of  an  oriental  market  quarter,  with  their  little  display  stands 
on  the  pavement  beside  them  and  with  the  buyers  grouped 
around,  joined  perhaps  by  curious  children  and  not  a  few 
curious  older  people,  commenting  pleasantly  or  sarcastically 
on  "the  way  these  Americans  do  things."  Imagine,  too.  the 
weather  to  be  the  Mediterranean  winter  with  the  sort  of  cold 
rain  that  Ave  have  here  in  October  or  March,  gradually  making 
mud  out  of  your  little  15-inch  spoil  bank  for  the  people  and 
the  donkeys  to  spread  in  a  slippery  layer  over  the  cobblestones ! 



[Jan.,  1911 

At  one  time,  when  the  rain  was  heavy  and  had  blocked  work 
for  five  or  six  days,  with  quite  a  stretch  of  pavement  in  bad 
shape,  a  young  Syrian  workman  remarked  that  we'd  better 
be  getting  something  done  pretty  soon,  "For,"  said  he,  in  his 
expressive  Arabic,  "those  shop-keepers  are  already  cursing  us 
with  curses  each  one  so  long,"  and  he  held  his  arm  out- 

View  of  a  Sidon    Street. 

It  was  with  considerable  relief  that  we  made  the  final  con- 
nection to  the  tanks  in  the  other  school,  opened  everything 
wide  and  watched  a  good  stream  slip  out  the  end  of  the  pipe. 
There  was  some  anxiety  even  then,  however,  for  the  new  string 
of  pipe  for  city  water  wouldn't  drip  a  drop!  We  found  that 
the  water  had  been  shut  off  for  a  day  or  so  because  of  the 

Vol.  Ill,  No.  1]   ARTESIAN  WATER  IN  ORIENT  :    FORD  61 

heavy  rains  that  muddied  the  river.  So  we  waited  till  it  was 
turned  on  and  still  no  flow.  By  opening  a  plug  at  a  low  point 
we  found  that  the  pipe  carried  water  but  could  not  get  it  at 
the  usual  height  of  delivery.  After  trying  various  means  we 
made  a  long  plunger  with  a  light  rod  and  two  or  three  leathers 
and  some  nuts,  and  worked  it  up  and  down  in  the  inlet  at  the 
stand-pipe  till  we  had  pumped  the  air  bubble,  which  was  evi- 
dently causing  the  trouble,  out  of  the  way  and  got  a  flow. 

Of  course  the  rams  had  been  at  work  some  years  before 
this  and  there  were  perhaps  one  or  two  others  in  the  country, 
but  except  for  the  regular  English  water-works  plant  in  the 
large  city  of  Beirut,  some  twenty-five  miles  away,  this  little  air- 
engine  constituted  the  only  intra-urban,  artificial  power  water 
works  in  all  that  part  of  the  country.  The  ram,  too,  described 
at  the  outset,  though  in  very  common  use,  would  seem,  so  far 
as  the  writer's  knowledge  goes,  to  be  quite  unique  in  having 
its  source,  its  active  parts,  and  its  waste  water  run-off  all  below 
the  surface  of  the  ground  from  twenty  to  forty  feet. 

Innumerable  incidents  of  both  technical  and  general  inter- 
est could  be  told  out  of  the  year's  experience  and  of  the  experi- 
ence of  three  previous  years,  but  those  given  will  afford  a 
glimpse  of  one  feature  of  this  curious,  new-old  country,  where 
American  educational  effort  has  wrought  a  peculiar  combina- 
tion of  the  habits  and  speech  of  two  thousand  years  ago  with 
the  newer  thought  and  industrial  methods  of  the  West. 



In  three  important  factors  the  electric  resistance  furnaces 
are  fundamentally  superior  for  most  industrial  operations  that 
come  within  their  scope ;  first,  in  the  quality  of  heat  they  pro- 
duce ;  second,  in  the  distribution  of  heat  throughout  the  work- 
ing chamber  that  is  possible  with  them ;  and  third,  in  the  means 
of  temperature  regulation  they  possess. 

As  to  the  first,  "electric"  heat,  as  developed  by  electrical 
resistance,  is  in  effect  quite  different  from  the  heat  produced 
from  such  other  sources  of  energy  as  coal,  oil  or  gas,  in  that 
it  is  not  the  result  of  the  process  of  combustion.  With  all  of 
these  latter  sources  another  element,  the  "supporter  of  combus- 
tion," is  of  course  absolutely  essential.  The  very  presence  of 
this  oxidizing  agent  is  for  most  purposes  detrimental  to  the 
quality  of  the  finished  product  in  hand.  Such  a  depreciating 
condition  is  entirely  unnecessary  to  the  development  of  even 
high  temperatures  by  electrical  resistance,  where  no  chemical 
changes  are  required  whatever. 

That  a  more  desirable  distribution  of  heat,  whether  uni- 
form or  definitely  varied,  is  possible  throughout  a  working 
chamber  heated  by  means  of  electrical  resistance  than  in  those 
heated  by  combustion,  of  any  fuel,  is  largely  due  to  a  me- 
chanical advantage.  In  the  former,  the  heat  is  generated  in 
the  actual  material  of  the  resistor,  while  in  the  latter  it  depends 
upon  a  process.  The  material  of  an  electrical  resistor  can  in 
general  be  arranged  to  better  advantage  in  the  structure  of  a 
furnace,  for  producing  the  desired  heat  distribution,  than  can 
the  mechanical  equipment  necessary  to  carrying  out  the  pro- 
cess of  combustion  (regardless  of  the  fuel). 

The  regulation  of  temperature  in  the  electric  furnace  is 
dependent  practically  upon  but  one  thing,  i.  e.^the  energy  sup- 
plied. While  this  is  mechanically  not  as  simple  to  control  as 
in  "combustion"  furnaces,  it  at  the  same  time  can  be  more 
uniformly  varied.  Again,  these  latter  furnaces  are-  compli- 
cated by  further  conditions,  viz.,  the 'supply  of  the  "supporter 
of  combustion"  must  be  controlled,  as  this  too  influences  the 
temperature,  and,  disposal  must  be  made  of  the  "products  of 
combustion"  resulting  from  their  operation. 

Recognizing  from  these  fundamental  principles,  the  ad- 
vantages of  electrical  operation,  a  line  of  Electric  Resistance 

"Class    of    19(17. 

With    the    Hosklns    Manufacturing    Company,    Detroit,    Mich. 

Vol.  Ill,  No.  1]      ELECTRIC  FURNACES:     BADGER  63 

Furnaces  has  been  developed  for  application  chiefly  to  the 
industrial  operations  involving  the  heating  of  metals  and 
metallic  parts  to  high  temperatures. 

Obviously  the  material  of  the  "resistor"  adapted  for  such 
furnaces  must  successfully  resist  the  action  of  the  temperatures 
it  is  desired  to  produce.  Graphite  or  carbon  was  chosen,  hav- 
ing the  desirable  properties  of  reasonable  mechanical  strength 
and  comparative  low  cost,  in  addition  to  its  very  high  refrac- 
tory powers.  As  heat  is  produced  in  these  furnaces  by  supply- 
ing electric  energy  to  their  resistors,  their  temperatures  may 
be  altered  by  varying  the  quantity  of  energy  so  supplied.  With 
a  constant  voltage  this  is  accomplished  naturally  by  varying 
the  resistance  of  the  working  circuit,  which  is  carried  out  by 
having  the  resistor  made  up  of  a  number  of  carbon  strips. 
Increasing  the  mechanical  pressure  on  these,  that  is,  by  forcing 
them  closer  together,  their  resistance  as  a  circuit  is  lessened 
and  they  draw  more  current,  with  resulting  rise  in  tempera- 
ture. Lessening  the  pressure  on  the  strips,  the  reverse  takes 
place.  This  is  the  familiar  principle  of  the  carbon-plate  rheo- 
stat, thouerh  in  the  furnace  carried  to  a  degree  hardly  sug- 
gested by  the  other. 

A  point  to  be  noted  is  that  in  the  furnace  itself  the  means 
of  temperature  variation  is  completely  within  the  working 
chamber,  so  that  the  change  comes  exactly  where  the  resulting 
effect  is  desired.  This  is  an  important  efficiency  consideration 
in  each  of  the  following  designs  of  the  Electric  Resistance  Fur- 
nace produced  under  the  patents  of  Albert  L.  Marsh  by  the 
Hoskins  Manufacturing  Company. 
Crucible   Design   Furnace 

The  chamber  walls  constitute  the  heating  unit  and  consist 
of  two  series  of  carbon  plates  in  contact  ("a"  and  "a,"  Fig.  1) 
and  the  graphite  end-blocks  "b."  These  are  under  a  slight 
longitudinal  pressure  from  the  electrodes  "c,"  which  are  also 
of  graphite.  Under  even  "ten-hour-a-day"  operation  a  set  of 
carbon  plates  will  last  over  a  week,  the  end-blocks  two  weeks 
to  15  days,  and  the  electrodes  a  month  or  more.  Renewal  of 
these  parts  is  obviously  very  simple. 

At  the  terminals  "e"  the  low-voltage  current  is  supplied, 
this  being  conducted  directly  to  the  electrodes  through  water- 
cooled  blocks  "f :"  "g"  indicating  the  inlet  and  outlet  for  the 
running  water.  The  hand  screws  "d"  serve  as  a  fine  means 
of  regulation  of  the  energy  supplied  by  varying  the  resistance 
— and  hence  the  resulting  temperature  in  the  chamber. 

A  thick,  highly  refractory  insulation  surrounds  the  heat- 
ing-unit walls  and  separates  them  from  the  outer  steel  casing. 



[Jan.,  1911 

This  insulation  is  both  to  withstand  the  high  temperatures  pro- 
duced and  to  conserve  within  the  chamber  the  maximum 
amount  of  heat  generated. 

The  various  sizes  made  of  this  design  operate  on  from  10 
to  30  volts,  alternating  current  being  preferable  so  that  these 
potentials  may  be  obtained  by  transformers.     In  a  furnace  of 

Fig.   1.     Crucible  Design  of  Electric  Resistance  Furnace. 

10"xl0"xl0"  chamber  dimensions,  a  pressure  of  30  volts  is  used. 
In  this  size  a  maximum  of  45  k.  w.  of  energy  will  run  the  cham- 
ber temperature  from  cold  to  about  2700°  F.  in  an  hour's  time. 
At  this  point  the  carbons  are  of  course  incandescent.  Once  at- 
tained, such  a  temperature  may  be  held  constant  while  drawing 
but  50%  of  its  initial  energy.    For  such  a  furnace  the  regula- 

Vol.  Ill,  No.  1]     ELECTRIC  FURNACES:     BADGER 


tion  at  any  time  may  be  considered  as  about  60%  to  75%  of  the 
maximum  power  consumption. 

Temperatures  up  to  3600°  F.  may  be  obtained  in  these  fur- 
naces and  due  to  this  high  range  they  are  used  for  melting 
platinum.  In  one  of  the  government  mints  they  are  applied 
to  the  melting  down  of  gold  and  silver.  Other  metals  such  as 
nickel,   iron,   copper,   brass,   steels  and  various   alloys  are,   in 

Fig.   2.      Crucible   Furnace   Showing  Transformer. 

crucible  charges,  melted  in  them.  They  may  be  used  as  well 
for  heating  barium  chloride  in  steel  treating,  for  heating 
cyanide  and  lead  baths  and  for  "fire"  assay  work. 

Muffle  Design  Furnace 

Exactly  the  same  principles  applied  to  the  "Muffle"  form 
of  furnace  are  illustrated  by  Fig.  3.  In  this  the  carbon  plates 
are  in  a  horizontal  position,  on  either  side  of  the  chamber,  a 
graphite  block  connecting  the  two  series  across  the  top  or  roof 
of  the  chamber.     A  vertical  regulating  pressure  is  applied  by 



[Jan.,  1911 

the  handscrews  which  may  be  seen  underneath  the  body  of  the 

In  this  furnace,  which  is  considerably  more  enclosed  than 
the  crucible  form,  the  safe  operating  temperatures  are  prac- 
tically limited  to  2500°  F.,  though  this  is  quite  high  enough  for 
the  principal  use  for  which  it  has  been  designed,  namely,  the 
hardening  of  steel  tools  and  parts. 


Muffle  Design  of  Electric  Resistance  Furnace. 

Almost  an  entirely  new  understanding  is  at  present  work- 
ing out  in  a  practical  way  on  the  subject  of  heat  treatment  of 
various  steels.  Scientific  methods,  in  place  of  the  customary 
shop-room  guess  work,  are  fast  being  developed  and  applied  to 
this  very  important  branch  of  machine  and  tool  production. 

Vol.  Ill,  No.  1]      ELECTRIC  FURNACES:     BADGER 


Foremost  in  this  movement  is  the  use  of  electricity,  both  to 
produce  the  required  heat  by  means  of  resistance,  and  to  meas- 
ure its  intensity  through  application  of  the  thermo-couple. 

Besides  the  fundamental  advantages  of  electrical  operation 
already  outlined,  the  electric  furnace,  shown  in  Fig.  3 — and 
again  as  part  of  the  installation  in  Fig.  4 — possesses  inherently 
the  desirable  quality  of  an  actually  reducing  chamber  atmos- 
phere while  operating.  This  is  brought  about  by  the  great 
affinity  the  incandescent  carbon  walls  exert  for  the  slight 
amount  of  oxygen  that  is  allowed  to  enter  while  raising  the 

Fig.  4. 

Electric  Furnace  for  Tool  Hardening  in  the  Plant  of  the  Link-Belt  Co. 

A  working  installation  is  shown  in  Fig.  4.  In  this  corner 
of  the  hardening  room  of  the  Link-Belt  Company's  Plant,  the 
electric  furnace  is  seen  to  the  left  of  the  center;  a  pre-heating 
furnace  being  on  its  left  and  an,  oil  bath  to  the  right.  The 
switchboard  contains,  besides  the  necessary  controlling  appa- 
ratus for  the  motor-generator  set  supplying  the  current,  a 
pyrometer  meter  indicating  the  temperatures  of  the  furnaces, 
in  each  of  which  a  thermo-couple  is  installed. 



[Jan.,  1011 

Tube  Design   Furnace 

A  third  design  of  this  type  of  furnace  is  shown  by  Figs.  5 
and  6.  In  this  the  heating  unit  is  composed  of* carbon  plates  in 
the  form  of  rings  "a,"  which  terminate  with  graphite  blocks, 
"b. "  The  pressure-regulating  hand  screws  are  indicated  by 
"d;"  "e"  being  the  electrical  terminals  and  "g"  the  water- 
cooling  connections. 

Tube     Design    of    Electric     Resistance    Furnace. 

Again,  due  to  the  enclosed  structure,  the  maximum  safe 
operating  temperature  of  this  furnace  is  about  2500°  F.  It  is 
used  particularly  for  heat-treating  special  steel  parts  such  as 

Fig.  6.     Tube  Furnace  Showing  Chamber  Opening  and  Adjusting  Hand-Screws. 

Vol.  ITT,  No.  lj      ELECTRIC   FURNACES:     BADGER 

drills,  taps  and  dies;  and  also  for  annealing  metal  tools  and 

The  objective  production  of  heat,  as  a  branch  of  the  elec- 
trical industry,  while  later  in  line  of  commercial  development 
than  cither  that  of  light  or  dynamic  power,  nevertheless  is 
growing  rapidly  in  importance.  The  fundamental  advantages 
of  electricity  as  a  form  of  working  energy  are  commanding  for 
it  the  same  considerations  that  are  now  so  widely  recognized  in 
the  other  branches  of  the  art. 


It  is  the  purpose  of  this  paper  to  discuss  some  of  the  de- 
vices which  are  in  use  for  the  measurement  of  temperature, 
with  special  reference  to  the  measurement  of  comparatively 
high  temperatures,  from  about  500°  F.  up.  Also,  the  errors 
to  which  such  instruments  are  subject  will  be  pointed  out,  and 
so  far  as  possible,  methods  of  avoiding  these  errors  will  be 

The  Mercurial  Thermometer 

The  instrument  in  most  general  use  for  the  measurement 
of  temperature  is  the  mercury-in-glass  thermometer.  Other 
liquids  than  mercury  are  sometimes  used  in  a  glass  thermom- 
eter, but  the  principle  is  the  same.  When  such  an  instrument 
is  used  at  a  temperature  of  500°  F.,  or  higher,  it  becomes  sub- 
ject to  errors  which  are  often  considerable,  and  which  the 
simplicity  of  the  instrument  tends  to  conceal. 

The  most  common  source  of  error  in  such  a  thermometer 
is  boiling  of  the  mercury,  which  may  occur  at  as  low  a  tem- 
perature as  300°  F.  This  produces  a  vaporization  of  a  portion 
of  the  mercury,  with  a  subsequent  recondensation  in  the  upper, 
cooler  part  of  the  capillary  tube.  This  trouble  can  be  over- 
come by  introducing  an  inert  gas,  such  as  nitrogen,  into  the 
capillary  tube  above  the  mercury.  As  the  mercury  rises  in 
the  tube  upon  an  increase  in  temperature,  the  gas  pressure 
is  increased  and  the  boiling  of  the  mercury  thus  prevented. 
This  precaution  is  observed  in  the  higher  grade  thermometers, 
but  instruments  are  on  the  market  which  are  subject  to  a 
considerable  error  from  the  boiling  of  the  mercury.  When 
using  a  thermometer  which  has  not  been  filled  with  nitrogen, 
a  good  precaution  to  observe  is  to  keep  the  top  of  the  mercury 
column  as  cool  as  possible,  and  so  prevent  boiling,  or  to  keep 
the  whole  stem  hot,  which  prevents  condensation  of  the  mer- 
cury. This  precaution  will  be  effective  up  to  350°  to  400°  F., 
but  for  higher  temperatures  a  nitrogen  rilled  thermometer 
should  always  be  used. 

After  a  thermometer  has  been  made  and  calibrated  it  may 
undergo  certain  changes  which  will  very  seriously  affect  its 
accuracy.  The  most  important  changes,  and  the  only  one 
which  need  be  considered  here,  is  a  permanent  contraction  of 

♦Class   of  1904,    Instructor   in   Experimental   Engineering,    Armour    Institute   of 

Vol.  Ill,  No.  1]   TEMPERATURE  MEASUREMENT  :    PEEBLES  71 

the  glass  which  renders  all  the  readings  of  the  instrument  high. 
This  is  caused  by  a  slow  readjustment  of  the  internal  stresses 
in  the  glass  which  were  produced  when  the  stem  was  made. 
Tests  made  by  the  writer  have  shown  thermometers  to  read 
as  much  as  60°  high  at  a  temperature  of  700°  F.,  due  to  the 
contraction  of  the  glass.  Errors  of  this  magnitude  were  found 
in  supposedly  high  grade  instruments,  much  above  the  average 
thermometer  to  be  found  in  the  market.  It  is  quite  probable 
that  many  thermometers  in  general  use,  the  indications  of 
which  are  accepted  as  correct  by  the  users,  would  be  found 
on  test  to  be  subject  to  errors  even  greater  than  this. 

In  the  manufacture  of  the  best  thermometers  the  glass 
stem  is  annealed  before  the  scale  is  etched  on.  This  is  done 
by  heating  the  stem  at  a  temperature  somewhat  above  the 
highest  at  which  it  is  to  be  used,  and  maintaining  it  at  that 
temperature  from  5  to  10  days.  It  should  then  be  cooled  very 
slowly,  the  cooling  lasting  from  4  to  6  days.  This  removes  all 
the  strains  from  the  glass  and  produces  a  thermometer  which 
will  not  change  with  age.  In  buying  a  thermometer  for  use 
in  work  where  reliable  indications  are  essential,  only  one 
which  has  been  properly  annealed  in  the  making  should  be 
considered.  Many  thermometers  which  have  not  been  thus 
artificially  aged  are  in  the  market. 

In  perhaps  the  majority  of  cases  where  a  thermometer  is 
used,  the  bulb  is  placed  in  contact  with  the  object  of  which 
the  temperature  is  desired,  while  a  considerable  portion  of 
the  stem  emerges  into  a  very  different  temperature.  For 
example:  Suppose  an  experimenter  wishes  to  determine  the 
burning  point  of  a  sample  of  gas  cylinder  oil.  The  bulb 
and  perhaps  a  small  portion  of  the  stem  are  immersed  in  the 
oil  at  a  temperature  of  say,  650°  F.  The  greater  portion  of 
the  stem  emerges  into  the  air  above  the  oil  bath,  the  average 
temperature  of  which  may  not  be  much  above  100°  P.  Most 
high  grade  thermometers  are  calibrated  under  a  condition  of 
total  immersion,  and  are  correct  for  that  condition  only.  When 
only  the  bulb  is  immersed  and  the  stem  emerges  into  the  air 
at  a  much  lower  temperature,  the  indications  of  the  instru- 
ment will  be  considerably  in  error.  The  amount  of  the  error 
will  depend  upon  the  difference  in  temperature  between 
immersed  and  emergent  parts,  the  number  of  degrees  on  the 
emergent  stem,  and  the  glass  of  which  the  stem  is  made. 

Stem  correction  =  Kn  (T°— 1°),  where  K  is  a  constant 
depending  on  the  glass,  n  is  the  number  of  degrees  on  emergent 
stem;  T°  is  the  temperature  of  the  immersed  part,  and  t°  the 
temperature  of  the  emergent  part.     The  value  of  K  must  be 

72  THE    ARMOUR    ENGINEER  [Jan.,  1911 

determined  experimentally  for  each  thermometer,  as  it  differs 
for  different  glass.  This  can  be  done  by  comparing  the  read- 
ing of  the  thermometer  when  exposed  to  a  given  temperature 
under  a  condition  of  total  immersion  with  the  reading  under 
a  condition  of  partial  immersion.  This  gives  all  the  factors 
in  the  above  equation  except  K,  which  may  therefore  be  calcu- 

In  the  thermometer  mentioned  above  in  connection  with 
the  test  of  cylinder  oil,  the  value  of  K  is  .00009.  The  oil  is 
at  a  temperature  of  650°  F.,  and  the  air  above  the  bath  at 
100°  F.  Hence  T°— 1°=650°— 100°=550°.  Assume  that  the 
stem  is  immersed  in  the  oil  to  the  50°  point.  The  stem  correc- 
tion is 

0.00009  (650—50)   (650—100)  =  29.7°. 

When  the  stem  is  colder  than  the  bulb  the  stem  correc- 
tion must  be  added  to  the  observed  reading.  Hence,  the  correct 
burning  point  of  the  oil  is  650°  +  29.7°  =  679.7°.  When  the 
stem  is  hotter  than  the  bulb  the  stem  correction  should  be 

A  reliable  mercury-in-glass  thermometer  should  be  well 
annealed  to  prevent  slow  contraction  of  bulb  and  stem  with 
age;  the  upper  part  of  the  capillary  tube  should  be  filled  with 
nitrogen  to  prevent  boiling  of  the  mercury;  and  the  stem  cor- 
rection should  be  known. 

Resistance  Thermometer. 

The  practical  limit  of  a  mercurial  thermometer  is  from 
800°  F.  to  900°  F.  Above  this  it  is  very  difficult  to  obtain 
reliable  results  with  a  mercurial  thermometer,  and  so  some 
other  method  becomes  necessary.  The  electrical  resistance  of 
the  metals  is  known  to  change  with  temperature,  and  since 
electrical  resistance  can  be  measured  with  considerable  ac- 
curacy this  furnishes  one  of  the  most  reliable  and  accurate 
methods  for  the  measurement  of  temperature. 

Platinum  is  practically  the  only  metal  which  has  come 
into  general  use  for  this  purpose  on  account  of  its  high  melting 
point  and  resistance  to  the  attack  of  gases  at  high  tempera- 
tures. The  first  electrical  resistance  thermometer  was  de- 
signed by  Sir  William  Siemens,  and  was  later  improved  and 
perfected  by  Callender  and  Griffiths.  Siemens'  instrument  was 
made  by  winding  fine  platinum  wire  on  a  fire  clay  cylinder 
and  surrounding  it  with  a  protecting  tube  of  porcelain  or 
quartz.     This  thermometer  was  found  to  be  sluggish  in  its 


action,  requiring  considerable  time  to  come  to  the  temperature 
of  the  surrounding  medium.  It  gave  very  good  results,  how- 
ever, where  the  temperature  was  nearly  constant,  as  would 
he  the  case  in  an  annealing  furnace. 

In  Callender's  instrument  the  platinum  wire  was  wound 
on  a  strip  of  mica  and  surrounded  with  a  steel  tube.  The 
porcelain  tube  is  very  fragile  and  was  found  to  break  with 
the  slightest  blow  when  hot.  It  is  also  very  likely  to  crack 
when  exposed  to  sudden  changes  in  temperature,  and  hence 
cannot  be  used  with  success  in  a  metal  bath.  The  Callender 
instrument,  with  steel  protecting  tube,  was  found  to  be  quite 
sensitive  and  extremely  accurate.  In  fact  the  resistance  ther- 
mometer is  probably  without  doubt  the  most  accurate  instru- 
ment that  we  have  for  the  measurement  of  temperature.  It  is 
a  matter  of  record  that  a  thermometer  of  this  type,  designed 
and  constructed  by  the  United  States  Bureau  of  Standards, 
reached  the  temperature  of  the  surrounding  medium  to  within 
1/1000  of  a  degree  Centigrade  in  three  seconds. 

Fig.    1.      Whipple   Indicator    with   Resistance    Thermometer. 

74  THE    ARMOUR    ENGINEER  [Jan.,  1911 

The  measurement  of  the  resistance  of  the  platinum  coil 
is  an  important  point  in  resistance  thermometry.  The  Wheat- 
stone  bridge  method  is  the  one  usually  employed,  involving 
the  use  of  a  galvanometer,  an  adjustable  resistance  and  a 
battery.  The  operation  consists  in  adjusting  the  variable 
resistance  in  one  branch  of  the  bridge  until  a  balance  is  ob- 
tained, indicated  by  a  zero  reading  of  the  galvanometer  when 
its  circuit  is  closed.  A  certain  amount  of  manipulation  is 
therefore  always  necessary  to  secure  a  temperature  reading 
with  a  thermometer  of  this  kind.  Hence  a  resistance  ther- 
mometer is  not  a  directly  indicating  instrument,  unless  the 
necessary  manipulation  is  done  automatically. 

A  well  known  form  of  instrument  for  use  with  a  resistance 
thermometer  is  a  Whipple  Indicator.  This  instrument  is  shown 
in  Fig.  1,  connected  to  the  thermometer  and  ready  for  use. 
It  consists  of  a  Wheatstone  bridge,  battery  and  galvanometer, 
contained  in  a  single  case  as  shown.  The  adjustable  resistance 
consists  of  a  coil  of  wire  wound  upon  a  drum  which  is  revolved 
by  hand  until  a  balance  is  obtained.  Since  the  temperature 
sought  depends  upon  the  resistance  of  the  platinum  coil  in  the 
thermometer,  and  since  this  in  turn  is  equal  to  or  proportional 
to  the  adjustable  resistance  on  the  drum,  at  the  time  a  balance 
is  obtained,  it  follows  that  the  temperature  scale  can  be  placed 
directly  on  this  drum.  Thus  it  is  that  instead  of  reading  the 
resistance  which  has  been  wound  upon  the  drum  we  read  the 
temperature  directly. 

Of  course  certain  known  points  must  be  located  on  this 
temperature  scale,  in  order  to  make  possible  the  step  from 
resistance  to  temperature.  The  freezing  points  of  certain  of 
the  metals  are  known  with  a  considerable  degree  of  accuracy, 
and  this  supplies  a  convenient  and  reliable  method  for  cali- 
brating an  instrument  of  this  kind. 

Resistance  thermometers  are  made  in  various  sizes  and 
lengths,  up  to  one  inch  in  diameter  and  about  thirty  inches  in 
length.  The  platinum  resistance  coil  usually  occupies  not 
more  than  four  inches  in  the  lower  end  of  the  protecting  tube, 
from  which  platinum  leads  are  run  to  binding  posts  on  the 
boxwood  head  at  the  other  end.  It  is  important  that  no 
change  in  the  resistance  of  these  leads,  due  to  temperature 
changes,  should  affect  the  measurement  of  the  resistance  of 
the  thermometer  coil.  For  this  reason  two  compensating  leads 
of  the  same  size  and  length  as  the  true  leads,  are  placed  side 
by  side  with  the  latter,  and  connected  to  two  separate  binding 
posts  in  the  boxwood  head.  "Any  change  in  the  resistance  of 
the  true  leads  is  balanced  by  an  equal  change  in  the  com- 



pensating  leads.  All  that  remains  to  be  done  is  to  connect  the 
compensating  leads  to  the  adjustable  resistance  of  the  Wheat- 
stone  bridge.  Thus  any  change  in  the  resistance  of  these  leads 
simply  adds  to  or  subtracts  from  the  adjustable  resistance  in 
exactly  the  same  magnitude  as  a  change  in  the  resistance  of 

Callender  Recorder. 

the  true  leads  affects  the  resistance  of  the  thermometer  coil. 
Since  the  adjustable  resistance  must  be  balanced  against 
the  thermometer  coil  when  a  reading  is  obtained,  it  follows 
that  the  changes  in  lead  resistance  are  eliminated.  Thus  an 
instrument  of  this  kind  becomes  independent  of  the  depth  of 
immersion,  a  very  important  point  in  high  temperature  ther- 

76  THE    ARMOUR    ENGINEER  [Jan.,  1911 

A  very  excellent  instrument  for  use  with  a  resistance 
thermometer  is  the  Callender  Recorder,  shown  in  Fig.  2.  This 
instrument  gives  a  continuous  record  of  temperature,  the 
chart  covering  a  period  of  twenty-four  hours.  In  this  recorder 
the  adjustments  of  the  Wheatstone  bridge  are  made  auto- 
matically by  means  of  magnets  and  clock  work.  Two  magnets 
are  made  use  of,  one  operating  when  the  current  through  the 
bridge  is  in  one  direction  and  the  other  when  the  current  is 
in  the  opposite  direction.  The  adjustable  resistance  is  operated 
by  the  clock  work,  the  magnets  simply  serving  to  release  a 
brake  which  holds  the  clock  in  check.  The  clock  operates  the 
adjustable  resistance  in  one  direction  or  the  other,  according 
to  which  magnet  has  operated.  As  soon  as  a  balance  is  ob- 
tained the  current  ceases  to  flow  through  the  magnet,  which 
immediately  lets  go  of  the  brake  and  stops  the  clock  motion. 

Thus,  all  the  manipulation  necessary  for  a  measurement 
of  resistance  is 'done  automatically  and  the  instrument  will 
give  a  continuous  record  of  temperature. 

Up  to  about  2200°  F.,  the  platinum  resistance  thermometer 
gives  the  most  accurate  measurement  of  temperature  that  we 
have.  The  only  objections  to  it  are  a  slight  change  in  the 
resistance  of  the  platinum  with  time,  and  the  fragile  character 
of  a  porcelain  or  quartz  protecting  sheath. 

Thermoelectric  Thermometer 

When  two  dissimilar  metals  are  fused  together  and  the 
junction  heated,  the  latter  becomes  a  source  of  electromotive 
force.  The  magnitude  of  this  electromotive  force  is  propor- 
tional to  the  temperature  to  which  the  junction  is  raised.  This 
fact  offers  a  simple  and  convenient  method  for  the  measurement 
of  comparatively  high  temperatures. 

Such  a  junction  of  two  different  metals  is  known  as  a 
thermo-electric  couple,  and  much  study  and  investigation  have 
been  devoted  by  physicists  to  the  thermo-electric  measurement 
of  temperature.  The  credit  for  finally  placing  thermo-electric 
pyrometry  on  a  satisfactory  basis  belongs  to  LeChatelier.  He 
made  a  couple  consisting  of  one  wire  of  pure  platinum  and  the 
other  an  alloy  of  90%  platinum  and  10%  rhodium.  This  is 
known  as  the  LeChatelier  couple  and  is  the  one  in  general  use 
at  the  present  time. 

In  the  commercial  application  of  this  principle,  the  two 
wires  forming  the  couple  are  first  fused  together,  and  then 
are  insulated  from  each  other  throughout  their  length  by 
winding  asbestos  thread  upon  them.     Each  wire  is  then  run 


through  a  small  porcelain  tube,  the  tubes  extending  almost  to 
the  junction.  The  whole  is  then  covered  by  a  large  porcelain 
or  quartz  tube,  and  the  two  free  ends  of  the  wires  led  to 
binding  posts  on  the  wooden  handle  or  socket  to  which  the 
enclosing  tube  is  fastened.  A  millivoltmeter  graduated  to  read 
temperature  in  degrees  completes  the  apparatus. 

The  magnitude  of  the  electromotive  force  produced  by 
such  a  couple  depends,  not  upon  the  absolute  temperature  of 
the  junction,  but  rather  upon  the  difference  in  temperature 
between  the  junction  and  the  other  ends  of  the  wires,  where 
they  are  connected  to  the  external  leads.  Hence,  we  have  the 
terms  "hot  junction"  and  "cold  junction"  to  designate  the 
different  ends  of  the  wires  forming  the  couple  or  "element." 
It  is  important,  therefore,  that  the  cold  junction  be  kept  at 
a  constant  temperature  while  the  thermo-couple  is  in  use. 
Neglect  of  this  precaution  may  lead  to  considerable  error  in 
the  indications  of  the  instrument. 

In  addition  to  its  simplicity  and  ease  in  handling,  the 
thermo-electric  pyrometer  has  the  advantage  of  a  very  small 
time  lag.  It  comes  quickly  to  the  temperature  of  the  medium 
in  which  it  is  placed,  and  hence  is  suitable  for  measuring 
changing  temperatures.  In  this  particular  it  is  superior  to  the 
resistance  thermometer,  but  is  not  capable  of  such  great 
accuracy  as  the  latter  instrument. 

The  sensibility  of  a  platinum-rhodium  thermo-couple 
diminishes  rapidly  below  500°  F.,  and  hence,  it  is  not  suited 
for  measuring  comparatively  low  temperatures.  In  the  range 
between  300°  F.  and  900°  F.,  the  best  results  are  obtained  from 
the  use  of  a  couple  of  copper  and  constantan  or  iron  and  Con- 
stanta n.  Such  a  couple  gives  a  much  greater  electromotive 
force  in  this  range  than  can  be  obtained  from  a  platinum-rho- 
dium couple,  and  hence  is  more  satisfactory. 

All  metals  disintegrate  more  or  less  when  exposed  to  high 
temperatures  for  a  considerable  length  of  time.  This  dis- 
integration of  the  metal  forming  a  thermo-couple  is  also  accom- 
panied by  a  loss  in  electromotive  force,  and  hence  after  long 
exposure  to  a  high  temperature,  the  indications  of  such  a 
couple  are  likely  to  be  somewhat  in  error.  If  platinum  be  kept 
at  a  dull  red  heat  (about  1800°  F.)  for  eight  hours  it  will 
suffer  a  loss  of  about  Yi%  in  electromotive  force.  Continued 
heating  will  not  increase  this  loss  materially,  and  when  it  is 
considered  that  all  other  metals  suffer  a  much  greater  loss,  it 
is  easily  seen  that  platinum  is  by  far  the  best  metal  for  a 

78  THE    ARMOUR    ENGINEER  [Jan.,  1911 

Optical  Pyrometers 

There  are  many  industrial  processes  carried  on  at  tempera- 
tures where  platinum  either  disintegrates  rapidly  or  fuses. 
Such  temperatures  are  to  be  found  in  the  electric  furnace, 
which  now  has  a  wide  commercial  application.  Manifestly 
none  of  the  temperature  measuring  devices  discussed  thus  far, 
as  electric  resistance  and  thermo-electric  pyrometer,  are  suit- 
able for  use  with  such  high  temperatures. 

For  some  time  it  had  been  the  custom  to  estimate  these 
temperatures  by  the  trained  eye  of  the  experienced  workman. 
But  this  method  was  only  approximately  correct  at  best  for 
the  same  eye  may  vary  considerably  in  the  estimation  of  color. 
This  crude  method,  however,  furnished  the  clue  to  the  discovery 
of  a  much  more  accurate  and  scientific  method,  whereby  the 
temperature  of  a  hot  body  is  measured  by  the  intensity  of  the 
light  which  it  radiates.  An  instrument  for  measuring  tempera- 
ture by  means  of  light  radiation  is  known  as  an  optical  pyro- 

The  principle  upon  which  optical  pyrometry  is  based  is 
known  as  the  Stefan-Boltzmann  radiation  law.  These  two 
physicists,  after  much  study  and  research,  succeeded  in  estab- 
lishing the  physical  law  that  the  total  energy  of  radiation  from 
a  hot  body  is  proportional  to  the  fourth  power  of  its  absolute 
temperature.  The  research  from  which  this  law  was  deduced 
is  discussed  by  Waidner  and  Burgess  in  Bulletin  No.  2  of  the 
United  States  Bureau  of  Standards. 

It  will  be  evident  that  if  it  is  possible  to  measure  the  total 
energy  of  radiation  with  a  fair  degree  of  accuracy,  we  imme- 
diately have  a  very  accurate  measure  of  temperature,  because 
the  latter  is  proportional  to  the  fourth  root  of  the  energy  of 
radiation.  Thus  a  considerable  error  in  the  measurement  of  the 
total  energy  of  radiation  will  give  a  very  small  error  in  the 
determination  of  the  temperature. 

Photometric  methods  have  been  made  use  of  for  the  pur- 
pose of  measuring  the  intensity  of  the  light  radiated  from  an 
incandescent  body,  and  along  this  line  the  optical  pyrometer 
has  been  worked  out.  The  method  consists  in  comparing  the 
intensity  of  the  light  from  the  hot  body  with  that  from  a 
standard  lamp,  by  ordinary  photometric  methods. 

One  of  the  best  optical  pyrometers  is  the  invention  of 
LeChatelier,  the  man  who  did  much  in  the  development  of  the 
thermo-electric  pyrometer.  Inasmuch  as  the  principle  used  in 
this  instrument  is  typical  of  all  others,  it  will  be  described 
rather  carefully,  from  which  it  should  be  possible  to  obtain  a 
fair  idea  of  the  optical  pyrometer  in  general. 



The  construction  of  the  instrument  may  be  seen  from  Fig. 
3.  A  small  gasoline  lamp  is  placed  at  A,  so>  that  light  from 
its  central  portion  passes  through  the  lense  B,  is  reflected  from 
the  45°  mirror,  brought  to  a  focus  by  the  eye-piece,  and  ob- 
served through  a  red  glass. 

This  provides  a  red  comparison  field  of  constant  intensity. 
The  lamp  A  is  mounted  eccentrically,  and  may  be  turned  so 
that  the  image  of  the  flame  is  exactly  bisected  by  the  edge  of 

"i  !  r 

H-       r     -W    ~Rbsorbiop  Gloss 

[~      ,    id 


L,eChatelier  Optical  Pyrometer. 

the  mirror  C.  Light  from  the  incandescent  body  under  ob- 
servation is  focused  by  the  objective,  passes  by  the  edge  of 
the  45°  mirror,  and  forms  a  red  field  immediately  beside  and 
touching  the  first. 

A  measure  of  temperature  is  made  by  bringing  the  two 
red  fields  to  the  same  brightness.  This  is  done  by  opening  or 
closing  the  iris  diaphragm  D  in  front  of  the  objective,  thus 

80  THE    ARMOUR    ENGINEER  [Jan.,  1911 

admitting  more  or  less  light  from  the  body  whose  temperature 
is  sought.  For  very  high  temperatures  additional  absorbing 
glasses  of  known  coefficients  of  absorption,  are  placed  below 
the  objective,  and  for  lower  temperatures  before  the  com- 
parison lamp.  The  opening  of  the  iris  diaphragm,  when  equal 
intensity  has  been  established,  is  read  upon  a  scale,  the  square 
of  whose  reading  is  a  measure  of  the  intensity  of  the  light 
from  the  incandescent  source. 

Since,  according  to  the  Stefan-Boltzman  law,  the  tempera- 
ture is  proportional  to  the  intensity  of  the  radiation,  we  have 
immediately  a  measure  of  the  temperature  when  we  have 
measured  the  intensity  of  the  radiation.  All  that  is  necessary 
is  to  have  two  sources  of  light  of  known  temperatures,  molten 
metal  for  example.  Note  the  reading  of  the  pyrometer  when 
focused  upon  each  of  these  bodies  and  plot  two  points  having 
for  their  co-ordinates  temperatures  and  scale  reading  on  the 
iris  diaphragm.  Draw  a  straight  line  through  these  two 
points,  produced  in  both  directions,  and  the  pyrometer  is  cali- 
brated for  all  temperatures. 

There  is  one  important  point  to  be  kept  in  mind  in  con- 
nection with  the  Stefan-Boltzman  law  quoted  above.  The  law 
is  true  only  for  what  is  technically  known  as  a  "black  body." 
The  conception  of  such  a  body  is  due  to  Kirchhoff,  who  defined 
it  as  a  body  which  would  absorb  all  radiations  falling  on  u 
and  would  neither  reflect  nor  transmit  any.  Kirchhoff  pointed 
out  that  the  radiation  from  such  a  body  is  a  function  of  the 
temperature  alone,  and  hence  may  be  used  to  measure  the 
temperature.  The  first  experimental  realization  of  such  a 
"black  body"  was  made  by  Wein  and  Lummer.  who  heated 
the  walls  of  a  hollow  opaque  inclosure  as  uniformly  as  pos- 
sible and  observed  the  radiations  coining  from  tin1  inside 
through  a  very  small  opening  in  the  walls  of  the  inclosure. 

It  is  evident  that  such  a  body  will  absorb  all  the  radia- 
tions incident  through  the  small  opening,  no  matter  what  the 
material  of  the  walls  may  be,  for  unless  the  walls  are  totally 
reflecting,  all  radiations  must  sooner  or  later  be  absorbed, 
except  that  portion  which  may  again  escape  through  the  small 
opening.  The  presence  of  this  small  opening  makes  a  slight 
departure  from  a  theoretical  black  body. 

No  body  is  known  whose  surface  radiation  is  that  of  a 
black  body.  The  radiations  from  carbon  and  iron  are  very  close 
to  black  body  radiation,  while  the  radiation  from  polished 
platinum  and  the  white  oxides  departs  very  evidently  from  it. 
It  follows,  therefor,  that  a  number  of  different  bodies  all  heated 
to  the   same   temperature   will   radiate    different   amounts   of 



energy,  and  hence  the  optical  pyrometer  would  show  tempera- 
tures for  them  all.  In  this  connection  the  term  "black  body 
temperature"  has  come  into  use.  Two  bodies  are  said  to  be  at 
the  same  black  body  temperature  when  they  radiate  the  same 
amount  of  energy.  Manifestly  they  are  not  at  the  same  tem- 
perature, and  hence  the  term,  black  body  temperature  violates 
the  conception  of  equal  temperatures  which  is  based  upon 
thermal  equilibrium  between  the  two  bodies  if  brought  into 

Nevertheless,  when  pyrometers  are  calibrated  in  terms  of 
black  body  temperature,  as  all  instruments  based  upon  the 
Stefan-Boltzman  law  must  necessarily  be,  the  conception  of 
equal  black  body  temperatures  is  of  great  practical  value. 

It   will   be   evident  from   the  foregoing   that   the   optical 

pyrometer  cannot  be  depended  upon  to  give  the  correct  ab- 
solute temperature  of  all  bodies.  It  will,  however,  repeat  its 
indications  upon  the  same  body  with  unerring  accuracy,  and 
in  a  large  number  of  industrial  operations  this  is  all  that  is 
required.  After  the  proper  temperature  for  any  operation 
has  been  discovered,  the  optical  pyrometer  will  make  it  pos- 
sible to  duplicate  this  temperature  day  after  day  with  great 

There  are  a  large  number  of  operations  where  the  radia- 
tion differs  but  slightly  from  that  of  a  black  body  and  hence 
the  optical  pyrometer  will  read  the  absolute  temperature  cor- 
rectly. A  boiler  furnace,  a  steel  furnace,  a  porcelain  kiln,  a 
pot  of  molten  glass,  an  electric  furnace,  hot  fire  brick,  etc., 
are  examples.  Thus  the  optical  pyrometer  has  a  wide  field 
for  usefulness  in  the  mechanic  arts. 

One  of  the  most  convenient  instruments,  based  upon  the 
energy  of  total  radiation,  is  Fery's  Thermo-electric  Telescope. 

82  THE    ARMOUR    ENGINEER  [Jan.,  1911 

This  instrument  combines  the  thermo-electric  and  optical  prin- 
ciples in  the  measurement  of  temperature  in  that  its  indications 
depend  upon  the  energy  or  radiation  and  are  obtained  from  a 
thermo-couple  and  galvanometer.  The  construction  is  shown 
in  Fig.  4.  Radiation  from  the  incandescent  body  passes 
through  the  lens  C  and  falls  upon  a  very  small  and  sensitive 
thermo-couple  shown  at  F  in  the  sketch.  A  diaphragm  D  D 
fixed  in  size  and  position,  gives  a  cone  of  rays  of  constant 
angular  aperture,  independent  of  the  distance  from  the  incan- 
descent body.  These  rays,  falling  on  the  thermo-couple,  pro- 
duce an  increase  in  temperature  proportional  to  the  total 
energy  of  radiation,  which  in  turn  induces  an  electromotive 
force  proportional  to  the  energy  of  radiation.  Thus  a  direct 
reading  is  obtained  upon  millivoltmeter  which,  according  to 
the  Stefan-Boltzman  law,  may  be  read  in  terms  of  temperature. 
The  leads  from  the  thermo-couple  are  led  to  the  binding  posts 
shown  at  P  P  in  the  sketch,  to  which  the  millivoltmeter  leads 
are  also  connected.  A  and  B  in  the  sketch  are  screens  placed 
on  each  side  of  the  thermo-couple  to  exclude  all  light  except 
that  which  comes  from  the  incandescent  source  under  obser- 
vation. E  is  the  eye-piece  by  means  of  which  the  image  of 
the  light  source  is  focused  on  the  thermo-couple. 

An  instrument  of  this  kind  is  independent  of  the  distance 
of  the  incandescent  body,  within  certain  limits,  as  will  appear 
from  the  following  considerations.  Tf  the  instrument  is  sighted 
on  an  incandescent  body  of  limited  dimensions,  the  amount  of 
radiation  passing  through  the  opening  in  the  diaphragm  D  D 
will  vary  with  the  distance  from  the  hot  body,  being  inversely 
proportional  to  the  square  of  the  distance.  If  the  thermo- 
couple were  of  such  size  as  to  receive  all  of  the  radiation  con- 
verged upon  it  by  the  lens  C,  then  the  indications  of  the  gal- 
vanometer would  decrease  as  the  distance  from  the  incan- 
descent source  increases.  But  the  thermo-couple,  however,  is 
not  large  enough  to  receive  all  of  the  radiation  converged 
towards  it.  The  image  of  the  source  of  light,  formed  by  the 
lens  C  is  large  enough  to  overlap  the  thermo-couple  on  all 
sides,  so  that  when  the  observer  sights  the  instrument  the 
thermo-couple  appears  as  a  dark  disc  in  the  center  of  a  bright 
field  of  light.  When  the  instrument  is  brought  nearer  to  the 
source  of  light,  thus  increasing  the  size  of  the  image  produced, 
the  only  effect  is  to  increase  the  amount  of  this  overlapping, 
while  the  thermo-couple  receives  no  more  radiation  than  be- 
fore. On  the  other  hand,  however,  if  the  instrument  be  with- 
drawn to  such  a  distance  from  the  source  of  light  that  the 
image  formed  is  not  large   enough  to   completely  cover  the 

Vol.  Ill,  No.  1]   TEMPERATURE  MEASUREMENT :    PEEBLES  83 

thermo-couple,  the  readings  obtained  will  he  too  low,  and  will 
become  less  as  the  distance  from  the  source  of  light  is  in- 

From  the  foregoing  it  will  be  evident  that  the  instrument 
is  independent  of  distance  only  within  certain  limits.  The 
image  of  the  incandescent  source  must  always  be  large  enough 
to  completely  cover  the  thermo-couple.  In  general,  the  diam- 
eter of  the  hot  body  should  measure  as  many  inches  as  the 
distance  from  the  instrument  to  the  hot  body  measures  yards. 

The  Fery  pyrometer  is  best  adapted  for  use  in  the  range 
from  1300°  F..  to  2800°  F.,  where  its  indications  are  sufficiently 
accurate  to  answer  all  requirements  of  industrial  work.  It 
should  not  be  forgotten,  however,  that  an  optical  pyrometer 
depending  for  its  reading  upon  a  measurement  of  the  energy 
of  radiation  reads  black  body  temperatures,  which  in  some 
cases  may  vary  considerably  from  true  temperatures.  But 
when  the  same  temperature  is  to  be  repeated  time  after  time 
in  the  same  process,  the  Fery  pyrometer  will  repeat  its  read- 
ings with  a  degree  of  accuracy  sufficient  for  all  practical  pur- 


BY  WILLIAM  T.  DEAN,  E.  E.* 

The  recent  successful  development  of  internal  combustion 
engines  in  large  sizes  suitable  for  use  with  blast  furnace  gas 
has  directed  the  attention  of  steel  works  engineers  and  man- 
agers to  the  possibility  of  electrically  driving  all  the  machinery 
in  such  plants. 

So  few  years  have  elapsed  since  the  electrical  department 
of  most  steel  plants  consisted  of  a  chief  electrician  and  one  arc 
lamp  trimmer,  that  the  growth  of  the  electric  drive  has  been 
almost  incredible.  Today  contracts  are  being  carried  out  in- 
volving the  complete  electrical  operation  of  mills  to  produce 
100,000  tons  of  rails  per  month,  where  the  motor  units  reach 
the  enormous  output  of  10,000  horse-power  each. 

In  this  country,  the  Edgar  Thomson  works  of  the  Carnegie 
Steel  Co.  has  the  honor  of  using  the  first  heavy  rolling  mill 
drive  by  electric  motors.  The  system  used  in  this  mill  (250 
volts  direct  current)  is  probably  the  most  expensive  in  first 
cost  and  least  economical  in  operation  that  could  have  been 
selected,  nevertheless,  the  installation  bas  been  a  notable  suc- 
cess from  the  beginning.  It  is  quite  probable  that  the  trans- 
mission line  for  the  light  rail  mill  at  the  Edgar  Thomson  works 
cost  as  much  as  the  two  1,500-horse-power  direct-current  motors 
used,  and  the  building  for  housing  the  starting  and  speed  con- 
trolling rheostats  would  accommodate  a  very  fair  boiler  plant. 

The  first  consideration  in  any  particular  case  involving 
electric  drive  is — will  it  pay?  Can  more  steel  be  turned  out  for 
a  given  cost,  or  the  same  steel  for  a  lower  cost  than  with  a 
steam  driven  mill  ?  The  next  question  is — will  the  electric  mo- 
tor meet  the  severe  requirements  of  steel  mill  practice  such  as 
continuous  operation  24  hours  per  day  and  30  days  per  month, 
will  it  withstand  severe  overloads  even  to  the  point  of  stalling, 
will  the  serious  mechanical  shocks  incident  to  rolling,  destroy 
bearings  and  deteriorate  insulation  to  such  an  extent  as  to  ren- 
der the  maintenance  cost  of  such  machines  prohibitive?  The 
comparative  costs  will  be  taken  up  later.  All  the  questions 
that  arise  affecting  the  adaptability  of  the  motor  for  rolling 
mill  operation  have  been  asked  and  successfully  answered  in 
the  past  as  applying  to  less  important  machinery.  The  solution 
of  the  problem  from  the  electrical  manufacturer 's  standpoint  is 

fAn  article  published  in  THE  IRON   TRADE  REVIEW. 

♦Class   of  1900.     District   Manager,    Power   and    Mining   Dept.,    General    Electric 
Co.,    Chicago. 

Vol.111,  No.  1]   ROLLING  MILL  ELECTRIC  DRIVE  :  DEAN  85 

only  one  of  degree  and  therefore  rests  with  the  designer.  That 
the  many  problems  entering  into  the  design  of  the  successful 
mill  motor  can  be  solved  is  evidenced  by  the  mills  now  being 
operated  electrically  and  by  those  undertaken  on  so  great  a 
scale  by  the  United  States  Steel  Corporation. 

The  ability  of  a  motor  to  operate  continuously  at  a  given 
load  is  only  limited  by  its  ability  to  radiate  the  heat  in  which 
the  relatively  small  energy  losses  appear. 

Constants  of  electrical  design,  such  as  safe  amperes  per 
square  inch  in  copper  conductors,  and  flux  densities  in  lami- 
nated steel,  are  well  known  to  the  electrical  designer  by  years 
of  experience.  Generators  of  as  great  capacity  as  the  largest 
motors  contemplated,  have  already  been  designed,  built,  and  are 
in  successful  operation.  It  may  be  conceded  then  with  refer- 
ence to  continuous  operation,  that  no  serious  difficulties  will  be 
encountered.  The  electric  motor  has  a  great  advantage  over 
the  steam  engine  in  the  matter  of  performance  under  overload. 
Speaking  of  the  induction  motor  particularly,  it  may  have  an 
overload  capacity  as  great  as  2y2  times  its  continuous  output 
and  the  motor  may  be  brought  to  a  complete  standstill  by  an 
unusual  overload  and  the  current  flowing  in  the  motor  wind- 
ings under  these  conditions  may  be  precisely  calculated  before 
the  motor  is  built,  and  provision  made  to  limit  the  maximum 
current  flowing  to  a  predetermined  value.  What  is  of  equally 
great  importance,  however,  is  the  fact  that  the  motor  current 
may  be  automatically  controlled  so  that  excessive  strains  cannot 

The  only  uncommon  problem  in  the  design  of  large  mill 
motors  aside  from  that  of  mere  size  is  that  of  mechanical  pro- 
portions to  withstand  shock  and  ordinary  wear.  It  is  in  this 
particular  that  the  electrical  manufacturer  has  been  obliged 
to  revolutionize  all  his  previous  ideas.  How  well  he  has  profited 
by  the  experience  of  the  engine  builder  may  be  gathered  from 
the  massive  construction  shown  in  the  illustrations. 

Many  of  the  mechanical  shocks  occurring  in  rolling  opera- 
tions with  steam  engines  are  due  to  the  reciprocating  motion 
of  the  engine  and  not  to  the  mill  and  gears.  All  such  shocks 
disappear  when  a  motor  is  used,  for  one  of  the  motor's  most 
valuable  characteristics  is  its  uniform  turning  moment. 

When  a  mill  is  driven  by  a  cross-compound  or  twin-tan- 
dem-compound engine  the  shaft  receives  its  turning  moment 
in  four  impulses;  if  the  cranks  are  quartered  there  are  four 
points  in  each  revolution  when  only  one  cylinder,  or  one  en- 
gine, if  twin  engines  are  used,  is  effective.  Very  heavy  fly 
wheels  must  be  provided  to  overcome  this  defect,  or  if  the 

THE    ARMOUR    ENGINEER  [Jan.,  1911 

mill  is  of  the  two-high  reversing  type,  each  cylinder  or  engine 
must  be  made  large  enough  to  provide  for  the  maximum  torque 
and  there  is  great  probability  of  entering  a  slightly  cold  bloom 
or  ingot  at  one  of  the  low  torque  points  in  the  cycle,  entailing 
backing  out  and  loss  of  time.  A  motor  having  uniform  turning 
moment  and  a  maximum  torque  of  2^  times  normal  full  load 
torque  could  experience  no  such  difficulties.  Indeed,  it  would 
be  a  very  poorly  heated  bloom  that  would  not  pass  through 
the  rolls.  As  a  matter  of  fact,  it  is  necessary  to  provide  auto- 
matic torque  limiting  controllers  not  to  protect  the  motor  but 
to  protect  the  rolls  and  gearing  between  the  motor  and  the 

Having  outlined  the  manifest  advantages  of  the  motor  for 
mill  driving,  the  cost  of  operating  a  steam  engine  and  an  elec- 
tric motor  must  be  compared.  Consider  a  mill  requiring  an 
engine  or  a  motor  of  a  given  rated  brake-horsepower,  and 
assume  a  non-reversing  three-high  mill  operating  practically 
continuously,  conditions  most  favorable  to  the  steam  engine. 
If  steam  must  be  generated  on  the  premises  the  engine-driven 
mill  will  be  most  economical  since  the  motor  must  be  charged 
with  the  cost  of  transformation  from  mechanical  into  electrical 
energy  at  the  engine  and  generator,  and  the  cost  of  transfor- 
mation from  electrical  into  mechanical  energy  at  the  motor  as 
well  as  the  transmission  losses.  Even  the  superior  economies 
of  large  steam  turbine  generator  units  will  not  overcome  such 
double  transformation  losses.  Assume,  however,  that  there  is 
a  distant  source  of  power,  natural  gas,  blast  furnace  gas,  coke 
oven  gas,  cheap  coal  or  water  power,  it  will  be  conceded  with- 
out argument  that  power  may  be  transmitted  more  econom- 
ically electrically  than  by  any  other  means.  It  remains  to  show 
the  relative  cost  of  transmission  and  the  adaptability  of  the 
possible  sources  of  power  to  rolling  mill  drive. 

The  internal  combustion  engine  is  not  adapted  to  the  direct 
driving  of  mills  on  account  of  its  inability  to  sustain  severe 
overloads  and  its  somewhat  instability  under  Widely  varying 
loads.  With  gas  power  available  the  question  narrows  to  the 
cost  of  the  transmission  of  gas  and  the  consumption  of  the 
same  under  boilers  at  the  mill,  as  compared  with  the  utiliza- 
tion of  the  gas  at  the  source  of  supply  to  produce  electrical 
power  for  transmission  to  motor  driven  mills. 

In  recent  blast  furnace  practice,  it  has  been  found  that 
approximately  123,000  cubic  feet  of  gas  is  produced  per  24 
hours  per  ton  of  pig  iron.  Two-thirds  of  this  is  available  for 
power  for  the  operation  of  blowing  engines  and  other  pur- 
poses, the  remaining  third  being  used  to  heat  the  air  blast.  A 
500-ton  furnace  will  produce  therefore  41,000,000  cubic  feet 

Vol.  Ill,  No.  1]    ROLLING  MILL  ELECTRIC  DRIVE  :   DEAN 


of  gas  per  24  hours.  Numerous  tests  have  shown  this  gas  to 
have  a  heat  of  combustion  of  100  B.  T.  U.,  or  more,  per  cubic 
foot.  Assuming  90  B.  T.  IT.  per  cubic  foot  as  a  conservative 
figure  the  total  heat  available  per  24  hours  is  3,690,000  B.  T.  U. 
The  heat  equivalent  of  one  horse-power  is  2,545  B.  T.  U.  There- 
fore, the  theoretical  power  available  from  the  gas  is  1,450,000 
horsepower-hours,  or  60,417  horsepower.  Assuming  the  net 
efficiency  of  the  gas  engine  at  22.5  per  cent  which,  if  in  error, 
is  too  high,  the  total  available  power  from  a  500-ton.  furnace 
is  13,600  horsepower. 

2000   H.   P.    Three-phase   Induction    Motor   Geared    to    Two-high   Blooming    Mills. 

On  account  of  the  lean  quality  of  blast  furnace  gas,  cylin- 
der dimensions  must  be  large  and  this  has  kept  the  size  of 
single  units  down  to  about  3,000  horsepower  and  generators 
rated  at  2,000  kilowatts  are  generally  used.  Such  generators 
have  an  efficiency  of  about  95  per  cent,  making  the  total  elec- 
trical energy  available  per  500-ton  furnace,  9,360  kilowatts. 
Of  this  power  about  600  kilowatts  is  required  to  operate  gas 
washing  machinery,  to  pump  jacket  water,  provide  exciting 
current  for  alternating  current  generators  and  minor  purposes, 
leaving  a  net  available  power  of  9,000  kilowatts.  From  the 
figures  above  we  have : 

THE    ARMOUR    ENGINEER  [Jan.,  1911 

153,750,000  =  total  B.  T.  U.  per  hour. 

2,545  =  B.  T.  U.  equivalent  to  1  horsepower,  theoretical 


3,420  B.  T.  U.  equivalent  to  1  kilowatt,  theo- 

0.746  retical 


45,000  kilowatts,  theoretical 


or  the  net  efficiency  of  the  entire  plant  will  be  20  per  cent. 

In  a  large  power  plant  using  steam  turbine  driven  genera- 
tors and  every  known  method  of  obtaining  high  efficiency,  it 
has  been  found  that  27,000  B.  T.  U.  in  the  coal  produce  one  kilo- 
watt at  the  switchboard.  This  is  under  regular  commercial 
conditions  and  includes  all  losses  such  as  banking  fires,  opera- 
tion of  boiler  feed  pumps,  circulating  pumps,  air  pumps,  coal 
and  ash  handling  machinery,  etc.,  and  the  plant  in  question  is 
subject  to  heavy  day  loads  and  light  night  loads.  Careful 
tests  at  this  plant  indicate  that  if  the  plant  could  be  operated 
with  a  constant  24-hour  load,  such  as  obtains  in  steel  mill  prac- 
tice, the  economy  would  be  23,000  B.  T.  U.  per  kilowatt  at 
the  switchboard.  In  a  similar  plant,  gas  fired,  but  subject  to 
a  steady  24-hour  load,  a  still  higher  economy  could  no  doubt 
be  secured  by  the  use  of  furnaces,  especially  designed  to  burn 
the  gas.  Assuming,  however,  a  fuel  economy  from  gas  of 
23,000  B.  T.  U.  per  kilowatt,  we  have : 

153,750,000  total  B.  T.  U. 

=  6,685  K.  W. 

23,000  B.  T.  IT.  per  kilowatt 

or  with  the  highest  type  of  plant  burning  the  gas  to  produce 
steam  and  using  turbo-generators  of  large  size  the  power  avail- 
able from  a  500-ton  blast  furnace  is  6,685  kilowatts. 

As  before  the  theoretical  power  available  is  45,000  kilo- 
watts, giving  a  net  efficiency  of  14.8  per  cent,  or  approximately 
three-fourths  the  efficiency  of  the  gas  engine  plant.  It  should 
be  noted  that  the  higher  output  of  the  gas  engine  plant  only 

Vol.  Ill,  No.  1]    ROLLING  MILL  ELECTRIC  DRIVE  :   DEAN 

applies  to  cases  where  blast  furnace  gas  is  available,  since  in 
producer  gas  plants  the  engine  must  be  charged  with  the  heat 
losses  in  the  gas  producer ;  moreover,  the  quality  of  coal  for  a 
gas  producer  must  be  much  higher  than  is  used  in  the  steam 
plant,  on  the  economy  of  which  the  above  calculations  are 

The  relative  reliability  of  the  gas  engine  and  steam  tur- 
bine plants  must  be  given  serious  consideration.  A  steam  tur- 
bine plant  may  be  operated  at  its  maximum  rating  indefinitely 
with  almost  absolute  freedom  from  shut-downs  or  necessity  of 
repairs.  The  gas  engine,  on  the  other  hand,  has  not  yet  reached 
a  perfection  of  development  where  it  may  be  depended  upon 
to  operate  24  hours  consecutively.  In  one  plant  of  this  nature 
containing  four  large  engines  where  in  emergency  one  unit 
could  carry  the  entire  load,  an  entire  shut-down  occurred,  all 
four  of  the  gas  engines  requiring  simultaneous  repairs.  The 
enormous  weights  of  the  reciprocating  parts,  the  great  cylinder 
dimensions,  the  rapid  and  wide  variation  in  temperatures  com- 
bine to  make  the  large  gas  engine  somewhat  unreliable.  That 
wider  experience  will  teach  engine  designers  methods  of  in- 
creasing reliability  cannot  be  doubted,  and  the  manufacturers 
of  this  class  of  prime  movers  are  to  be  congratulated  that  the 
great  steel  interests  of  the  country  are  willing  to  invest  their 
capital  so  as  to  promote  so  important  a  development. 

Gas  engine  builders  have  made  many  claims  as  to  the  re- 
liability of  their  apparatus,  most  of  which  are  based  on  Euro- 
pean practice.  To  those  in  possession  of  reliable  data  on 
European  practice,  such  claims  are  taken  with  a  degree  of 
allowance,  as  the  following  quotation  from  Engineering  (Lon- 
don) testifies: 

"In  this  connection  we  may  note  that  we  recently  heard 
of  a  large  continental  power  station  where  it  has  been  deemed 
advisable  to  install  a  reserve  plant  of  200  per  cent  of  the  nomi- 
nal capacity  of  the  station.  As  opposed  to  this,  some  English 
builders  of  turbo-generators  are  advocating  the  absolute  aboli- 
tion of  all  reserve  whatever,  apart  from  that  provided  by  the 
by-pass  valve,  enabling  the  unit  to  take,  if  necessary,  an  over- 
load of  50  to  100  per  cent. 

"Certainly  the  large  continental  gas-engine  may  be  a  suc- 
cess if  judged  from  a  non-commercial  standpoint.  So  long  as 
it  works,  it  undoubtedly  produces  power  very  economically, 
but  those  who  have  had.  most  experience  with  them  are  the 
very  ones  who  have  the  longest  catalog  of  their  defects." 

Early  in  1904,  contracts  were  let  for  gas  engines  and  elec- 
tric generators  of  a  total  capacity  of  8,775  kilowatts  for  Jo- 



[Jan.,  1911 

Vol.  III.  No.  11    ROLLING  MILL  ELECTRIC  DRIVE  :   DEAN  91 

hannesburg.  South  Africa.  It  was  not  until  1906  that  power 
was  first  delivered  and  the  supply  was  extremely  unreliable. 

Quoting  from  The  Engineer : 

"On  one  occasion  when  five  engines  of  7,000  horsepower 
were  running,  in  the  space  of  a  quarter  of  an  hour,  every  man 
in  the  engine  room  but  one  was  rendered  unconscious  from  gas 
poisoning.     *     * 

At  a  coroner's  inquest  held  in  May  (1907)  on  a  gas  fatality, 
it  was  stated  that  63  cases  of  poisoning  had  occurred  in  six 
months.     *     * 

At  last  on  May  15  the  plant  was  finally  shut  down.  The 
engine  contractors  threw  up  the  contract  and  admitted  that 
they  could  not  get  the  plant  into  shape  to  pass  the  specified 
tests.     The  town  council  then  rejected  the  plant.     *     * 

In  a  report  dated  March  1  last,  the  general  manager  stated 
that  owing  to  continued  break-down  the  whole  of  the  generator 
sets  had  never  been  available  for  use  at  one  time.     *     * 

The  direct  current  plant  of  5,400  kilowatts  had  had  the 
greatest  difficulty  in  dealing  with  the  maximum  load  of  2,750 
kilowatts,  and  it  had  not  been  found  possible  to  run  the  alter- 
nating current  generators  in  parallel  on  account  of  the  un- 
steady running  of  one  of  them.  The  generator  sets  could  not 
be  got  to  give  more  than  80  per  cent  of  their  normal  full  load, 
and  it  was  seldom  that  two-thirds  of  the  plant  was  fit  to  run. 
For  the  three  and  one-half  months  ended  Feb.  28  (1907)  the 
total  works  cost  had  been  5.1  cents  per  kilowatt-hour  as  com- 
pared with  the  original  estimate  of  1.72  cents." 

A  complete  turbine  plant  of  large  size,  including  the  best 
machinery,  boilers,  auxiliaries,  etc.,  and  the  highest  type  of  sta- 
tion construction  can  be  built  for  at  least  60  per  cent  of  the 
cost  of  a  blast  furnace  gas  engine  plant  of  the  same  capacity 
with  its  auxiliaries.  Assuming  as  arbitrary  figures  that  a  steam 
turbine  plant  can  be  built  for  $60  per  kilowatt,  and  that  a  gas 
engine  plant  can  be  built  for  $100  per  kilowatt,  and  that  a  plant 
of  40,000  kilowatts  average  capacity  is  required,  the  investment 
in  the  turbine  plant  will  be  $2,400*000. 

It  is  to  be  remembered  that  the  figure  for  the  gas  engine 
plant  is  undoubtedly  low  when  all  the  elements  are  considered 
and  that  a  turbine  plant  can  be  built  for  $45.00  per  kilowatt 
where  no  coal  storage  plant  is  required,  and  further  that  a  tur- 
bine plant  can  be  built  for  $40.00  per  kilowatt  where  cheap  real 
estate  is  available.  My  assumed  figure  of  $60.00  per  kilowatt 
is  based  on  a  complete  coal  burning  plant  with  coal  and  ash 
handling  machinery  and  includes  real  estate  in  a  great  city 
where  land  values  form  a  considerable  portion  of  the  total  in- 

92  THE    ARMOUR    ENGINEER  [Jan.,  1911 

vestment.  These  modifications  make  a  very  material  difference 
in  the  total  investment  in  a  large  plant,  and  on  this  point  the 
showing  in  favor  of  a  turbine  plant  is  much  greater  than  indi- 
cated in  this  article. 

The  gas  engine  plant,  however,  will  require  at  least  25  per 
cent  excess  in  capacity  in  order  to  maintain  the  average  out- 
put given  above  and  many  engineers  think  that  in  the  present 
stage  of  the  art,  50  per  cent  excess  capacity  should  be  installed. 
The  investment  in  the  gas  engine  plant  will  therefore  be  $5,000,- 
000,  or  108.2  per  cent  in  excess  of  the  investment  in  the  steam 
turbine  plant.  The  interest  on  $2,600,000  (the  difference  in 
investment)  at  5  per  cent  is  $130,000  per  year,  or  sufficient  to 
buy  86,750  tons  of  coal.  If  this  coal  were  burned  under  boilers 
in  addition  to  the  gas  obtained  from  the  blast  furnaces,  it 
would  generate  86,750,000  kilowatt-hours  or  1,156  kilowatts  24 
hours  per  day,  26  days  per  month,  throughout  the  year.  This 
figure  makes  a  very  respectable  addition  to  the  power  given 
above,  which  may  be  legitimately  expected  to  be  generated  by 
the  steam  turbine  plant,  and  leaves  a  relatively  small  margin  of 
total  power  in  favor  of  the  gas  engine  plant. 

From  this  showing,  the  plants  depending  entirely  on  gas 
engines  must  face  very  unfavorable  conditions.  They  will  have 
on  their  hands  enormously  expensive  plants,  requiring  four  or 
five  times  as  much  labor  as  the  equivalent  steam  turbine  plant 
with  constant  danger  of  delay,  due  to  break-downs  and  with 
maintenance  expenses  reaching  large  figures. 

In  addition  to  all  inherent  disadvantages  of  the  gas  engine 
plant  previously  noted,  the  fact  must  not  be  overlooked  that  in 
the  space  occupied  by  one  2,000-kilowatt  gas  engine  generator, 
a  steam  turbine  unit  having  a  rating  of  14,000  kilowatts  can  be 
installed  with  all  its  accessories,  and  that  a  gas  washing  plant 
used  with  the  gas  engines  requires  more  space  than  a  boiler 
plant  for  an  equivalent  turbine  installation.  In  fact,  a  gas 
engine  plant  with  its  accessories,  requires  so  much  space,  both 
in  the  engine  room  and  out,  that  considerable  difficulty  must  be 
experienced  to  properly  operate  all  sections  as  a  unit  plant. 

Earlier  in  this  discussion  it  was  proposed  to  pipe  the  waste 
gases  to  the  rolling  mills  and  there  generate  steam  for  the 
operation  of  mill  engines.  Neglecting  losses  in  piping  which 
will  exceed  the  losses  in  electrical  transmission,  this  system 
would  show  a  lower  economy  than  the  turbo-generator  system 
by  the  amount  that  the  reciprocating  engine  falls  below  the 
turbine  in  efficiency.  Non-reversing  mill  engines  of  large  size 
under  favorable  conditions,  operating  condensing,  require  ap- 
proximately 14  pounds  of  steam  per  brake-horsepower-hour. 

Vol.  Ill,  No.  1]   ROLLING  MILL  ELECTRIC  DRIVE  :   DEAN 


Large  size  turbines  only  require  about  9.4  pounds  of  steam  per 
brake-horsepower-hour.  The  total  efficiency  of  such  a  system 
would  be 


X  11.15  —  7.5  per  cent. 

For  purposes  of  comparison  on  the  mill  basis  the  efficiency 
figures  on  the  turbo-generator  system  and  the  gas  engine  plant 
must  be  decreased  by  the  losses  in  the  mill  motor.    Such  a  mo- 
tor will  have  a  full  load  efficiency  of  about  93  per  cent. 

Primary    Control    for    Three    6000    H.    P.    Induction    Motors. 

The  relative  efficiency  of  the  three  systems  of  utilizing  the 
waste  gases  are  at  follows : 

Per    cent 

(1)  Gas  transmitted   to  mill  to   produce   steam 

for  mill  engine    7.5 

(2)  Gas  burned  at  source  producing  steam  for 

turbo-generators,  energy  transmitted  elec- 
trically to  mill  motor   15 .  17 

(3)  Gas  used  in    internal    combustion   engines 

driving    generators,    energy    transmitted 
electrically  to  mill  motor 18 . 6 

94  THE    ARMOUR    ENGINEER  [Jan.,  1911 

The  above  figures  should  not  be  taken  as  absolute  but  give 
fairly  correct  relative  values,  and  clearly  indicate  the  wisdom 
of  motor  driving  rolling  mills.  The  writer  believes  that  the 
steam  turbine  system,  while  not  the  highest  in  efficiency,  will 
provide  ample  power  for  all  rolling  mill  purposes.  If  such  is 
the  case,  the  greater  reliability  of  the  steam  turbine  system  far 
outweighs  the  lower  fuel  economy,  and  the  extra  investment  in 
a  gas  engine  plant  will  only  pay  in  case  there  is  a  profitable 
market  for  the  excess  power  outside  of  the  steel  mill  proper. 

There  is  another  source  of  electrical  power  for  existing 
steel  plants  which  is  extensively  used  in  Europe  but  has  only 
been  utilized  in  one  case  in  this  country  and  that  on  a  relatively 
small  scale.  I  refer  to  the  steam  regenerator  and  low  pressure 
turbo-generator  receiving  an  intermittent  steam  supply  from 
reversing  mills  or  from  non-reversing  mills  subject  to  wide 
variations  in  load  or  speed,  or  both,  and  delivering  a  constant 
supply  of  electrical  energy. 

A  large  reversing  engine  requires  60  pounds  of  steam  (or 
more)  per  horsepower.  A  steam  turbine  operating  between  15 
pounds  absolute  pressure  and  28  inches  vacuum  requires  45 
pounds  of  steam  per  kilowatt-hour.  Thus,  there  is  available 
1.33  kilowatts  in  electrical  energy  for  each  horsepower  of  such 
engines,  more  than  enough  to  operate  a  duplicate  mill  electric- 
ally. The  gain  by  such  an  installation  is  all  "velvet"  and  re- 
quires a  relatively  small  outlay  of  capital. 

In  choosing  a  system  of  transmission  and  utilization  of  the 
electric  drive  the  steel  works  engineer  is  at  first  inclined  toward 
direct  current,  owing  to  his  greater  familiarity  with  that  sys- 
tem and  to  its  apparent  simplicity.  A  direct  current  system 
has  some  advantages  such  as  the  extension  of  an  existing  plant 
to  care  for  the  heavier  requirements  of  rolling  mill  drive.  How- 
ever, unless  the  centers  of  distribution  of  the  power  are  very 
close  to  the  generators,  the  transmission  line  will  be  so  expen- 
sive as  to  be  prohibitive.  If  an  alternating  current  system  is 
selected  the  cost  of  the  transmission  line  may  be  reduced  to  a 
relatively  small  proportion  of  the  plant  equipment. 

A  universal  formula  for  copper  in  a  transmission  line  of 
whatever  system,  voltage  or  frequency  is  the  following : 

D  X  W  X  C 

P  X  E2 

where      A  =  area  per  conductor  in  circular-mils, 

D  =  distance  of  transmission   (one  way)   in  feet, 

Vol.111,  No.  1]    ROLLING  MILL  ELECTRIC  DRIVE:   DEAN  95 

W  =  total  watts  delivered  at  end  of  line, 
C  =  constant  depending    on    the  system  and   power 

factor  if  alternating  current, 
p  =  percentage  of  loss  in  power  delivered, 
E  =  voltage  at  end  of  transmission  line. 

The  constant  C  has  the  following  values  for  the  various 
svstems  employed : 

Value    of    "C" 

Per  cent  power  factor 100         95         90         85         80 

Direct  current   2160      

Alternating      current,      single 

phase    2160     2400     2660     3000     3380 

Alternating  current,  2  phase..   1080     1200     1330     1500     1690 
Alternating  current,  3  phase..   1080     1200     1330     1500     1690 

As  an  example  in  point  let  us  consider  the  relative  cost  of 
transmitting  5,000  kilowatts  a  distance  of  2,000  feet  by  direct 
current  at  220  volts  and  by  alternating  current  at  the  same 

From  the  above  formula  : 
For  direct  current 

2,000  X  5,000,000  X  2,160 

A  = ■ =  44,628,100 

10  X  220  X  220 

Assuming  a  loss  of  10  per  cent,  two  conductors  of  this  cross 
section  each  2,000  feet  long  will  be  required,  and  since  the 
weight  of  one  foot  of  copper  having  an  area  of  one  circular-mil 
is  0.00000302  pound,  the  weight  per  foot  of  the  above  conductor 
would  be  134.77  pounds,  and  the  total  weight  of  copper  required 
would  be  539,107  pounds  or  over  269  tons  of  copper,  not  includ- 
ing insulation.  At  20  cents  per  pound  the  copper  alone  for  such 
a  line  would  cost  $107,821.40. 

For  alternating  current, 

2,000  X  5,000,000  X  1,690 

A  = =  34,917,024. 

10  X  220  X  220 

Assuming  the  same  energy  loss  as  before  and  a  power  fac- 
tor of  80  per  cent,  three  conductors  (for  three-phase  transmis- 
sion) of  this  cross  section  each  2,000  feet  long  make  a  total 
weight  of  copper  of  632,702  pounds,  which  at  20  cents  per 
pound  would  cost  $126,540.40. 



[Jan.,  1911 

Vol.  Ill,  No.  1]    ROLLING  MILL  ELECTRIC  DRIVE  :   DEAN  97 

From  the  above  it  is  evident  that  at  low  power  factor  and 
equal  voltages  the  alternating  current  transmission  system 
would  be  more  expensive  than  the  direct  current.  By  reason 
of  commutation  and  insulation  difficulties,  direct  current  volt- 
ages cannot  be  greatly  increased ;  on  the  other  hand  there  is  no 
reason  why  alternating  current  generators  and  motors  cannot 
be  built  to  operate  at  6,600  volts  or  even  higher  and  by  the  in- 
terposition of  transformers  the  transmission  voltage  may  even 
be  raised  to  100,000  or  150,000  volts. 

Assuming  a  transmission  at  6,600  volts  the  area  of  a  con- 
ductor becomes : 

2,000  X  5,000,000  X  1,690 

A  = =  38,800. 

10  X  6,600  X  6,600 

The  current  per  phase  for  the  above  6,600-volt  circuit  is 
545  amperes.  It  is  not  safe  to  allow  less  than  1,000  circular 
mils  per  ampere,  hence  54,500  circular  mils  or  more  per  con- 
ductor must  be  used.  The  next  larger  commercial  size  of  wire 
is  No.  2  B.  &  S.  gage,  which  has  an  area  of  66,000  circular-mils. 
Substituting  this  area  in  the  above  equation  and  solving  for 
the  value  of  P  we  find  the  power  loss  to  be  5.82  per  cent.  The 
three  conductors  of  No.  2  wire  would  have  a  weight  of  1,205 
pounds  and  would  cost  $241.80.  Thus  by  using  alternating 
current  at  6,600  volts,  the  cost  of  copper  has  been  reduced  to  an 
insignificant  sum  and  the  power  loss  cut  in  two.  If  the  power 
loss  were  further  reduced  50  per  cent  ,the  cost  of  the  copper 
would  only  be  $323.20.  It  is  true  that  insulators  for  6,600  volts 
cost  more  than  for  220  volts,  still  in  this  case  the  fewer  number 
required  and  the  greatly  reduced  labor  cost  overwhelmingly 
favor  the  alternating  current  high  voltage  system. 

The  saving  is  proportional  in  all  cases.  A  few  summers 
ago,  the  writer  had  occasion  to  figure  on  a  system  involving 
three  500-kilowatt  generators  with  a  transmission  of  2,000  feet. 
The  purchaser  was  offered  three  500-kilowatt,  2,300-volt  alter- 
nating current  generators,  three  500-kilowatt  rotary  converters 
with  all  necessary  switchboards  and  the  copper  for  the  trans- 
mission line  for  a  sum  about  $45,000  lower  than  he  paid  for  the 
250-volt  apparatus  and  line  decided  upon.  The  consulting  engi- 
neer in  charge,  while  an  excellent  blast  furnace  man,  knew 
nothing  of  electrical  matters  and  allowed  his  client  to  pay  the 
extra  cost  for  a  plant  which  must  sooner  or  later  be  remodeled 
to  an  economical  basis. 

Alternating  current  motors  are  now  offered,  which  success- 



[Jan.,  1911 

Vol.  Ill,  No.  1]   ROLLING  MILL  ELECTRIC  DRIVE  :  DEAN 

fully  perform  all  the  functions  of  direct  current  motors  and 
have  many  superiorities,  such  as  absence  of  commutator  and 
ability  to  handle  extreme  overloads.  These  motors  are  built  in 
all  sizes  for  the  operation  of  roller  tables  as  well  as  for  the  oper- 
ation of  the  main  rolls,  hence,  there  is  no  longer  an  excuse  for 
the  direct  current  system  where  large  powers  are  used. 

The  particular  voltage  to  be  selected  depends  on  tbe  dis- 
tance of  transmission  and  the  amount  of  power  transmitted  as 
shown  by  the  above  examples.  Consideration  should  also  be 
given  to  the  possible  expansion  of  the  plant.  For  a  plant  gen- 
erating 10.000  kilowatts  or  more.  6.000  volts  should  be  the  mini- 
mum for  transmissions  of  a  mile  or  so.  The  choice  of  frequency 
is  limited  to  25  or  60  cycles.  The  lower  frequency  is  prefer- 
able, owing  to  the  lower  motor  speeds  obtainable  with  reason- 
able cost.  The  speed  of  an  induction  motor  is  inversely  propor- 
tional to  the  number  of  its  poles  and  directly  proportional  to 
the  frequency  of  the  source  of  supply.  If  the  frequency  be 
stated  in  alternations  per  minute,  the  speed  will  be 


of  the  alternations,  where  N  represents  the  number  of  poles. 
Thus,  a  six-pole  25-cycle  (3.000  alternation)  motor  will  have  a 
synchronous  speed  of  500  revolutions  per  minute,  while  a  six- 
pole  60-eycle  (7,200  alternation)  motor  will  have  a  synchronous 
speed  of  1,200  revolutions  per  minute.  The  difference  in  fre- 
quency becomes  very  apparent  in  large  slow  speed  motors  for 
direct  connection  to  rolling  mills. 

Such  a  motor  operating  at  75  revolutions  per  minute  would 
have  40  poles  if  25  cycle,  and  96  poles  if  60  cycle.  A  large  num- 
ber of  poles  makes  a  difficult  design  unless  very  great  diameters 
are  used  and  in  any  case  has  a  very  bad  effect  on  the  constants 
of  the  machine,  particularly  the  power  factor.  Unquestionably 
a  frequency  of  25  cycles  is  preferable  for  power  purposes. 

The  question  of  suitable  speed  for  a  motor  driving  a  rolling 
mill  should  be  solved  by  the  mill  engineer  rather  than  the  motor 
manufacturer.  The  former  should,  however,  bear  in  mind  the 
limitations  of  speed  within  which  the  latter  must  work.  Prob- 
ably the  lowest  speed  for  direct  connection  to  rolls  which  would 
be  considered  would  be  50  revolutions  per  minute  for  25-cycle 
motors.  The  accompanying  table  gives  the  synchronous  speeds 
possible  and  the  probable  full  load  speeds  for  large  25-cycle 

100  THE    ARMOUR    ENGINEER  [Jan.,  1911 

Synchronous  and  Full  Load  Speeds  for  25-Cycle  Motors. 

Synchronous  Full  Load 





























42  . 























.  115.40.  . 




20  '.'..'..'. 










16  . 













375  00 



500  00 .  . 







......  1440.00 

Whenever  the  speed  of  the  rolls  exceeds  55  revolutions  per 
minute  it  is  preferable  and  cheaper  to  direct-connect  the  motor 
than  to  employ  a  great  reduction.  This  refers  to  mills  requiring 
motors  of  3,000  horsepower  and  larger  for  a  single  roll  stand, 
and  to  many  cases  where  smaller  motors  would  be  employed. 
Where  it  is  necessary  to  drive  more  than  one  roll  stand  from  a 
single  motor,  thus  entailing  gearing  which  would  in  any  case 
be  charged  against  the  mill,  a  higher  speed  motor  should  be 
used,  but  in  no  case  should  the  gear  ratio  be  greater  than  3:1. 
For  motors  of  2,500  horsepower  or  larger,  a  lower  gear  ratio 
should  be  selected. 

Vol.  Ill,  No.  1]    ROLLING  MILL  ELECTRIC  DRIVE :   DEAN 


For  a  close  group  of  small  mills,  each  of  which  in  succes- 
sion does  a  portion  of  the  total  work  of  reducing  a  bloom  to  a 
commercial  shape,  the  most  economical  drive  is  by  a  single 
motor.  This  is  due  to  the  higher  efficiency  of  a  single  motor  of 
large  size  over  several  small  motors  and  to  the  fact  that  such  a 
motor  may  be  operated  at  more  nearly  its  full  load  continuously. 
The  first  cost  of  such  a  plant  will  be  appreciably  lower  when  a 
single  large  motor  is  installed. 

The  method  of  driving  a  group  of  small  mills  from  a  single 
motor  must  be  very  carefully  considered  in  each  case.  If  bevel 
gears  are  used  the  driving  shaft  must  operate  at  a  relatively 
low  speed  in  order  to  avoid  the  use  of  too  high  a  gear  ratio 

75  100  «25 


Curves   showing  efficiency   and   power   factor  of  a   5000-Horsepower   Mot 
designed   for  various   synchronous   speeds. 

102  THE    ARMOUR    ENGINEER  [Jan.,  1911 

between  the  shaft  and  rolls.  This  means  a  low  speed  and  con- 
sequently an  expensive  motor.  If  the  conditions  will  allow  the 
use  of  a  rope  drive  the  motor  may  have  a  fairly  high  speed  and 
the  total  friction  loss  may  be  reduced.  It  is  probable  that  the 
maintenance  cost  of  a  rope  drive  for  a  group  of  small  mills  will 
be  lower  than  for  the  equivalent  bevel  gear  drive.  Any  flexible 
connection,  such  as  a  rope  drive  between  the  mills  and  the  mo- 
tor, will  be  favorable  to  the  operation  of  the  latter.  In  general 
it  may  be  said  that  the  higher  the  motor  speed  adopted  the  bet- 
ter will  be  the  efficiency  and  power  factor.  This  is  shown  by  the 
curves  giving  approximate  value  of  power  factor  and  efficiency 
for  a  5,000-horsepower  motor  designed  for  various  synchronous 

Summarizing  the  various  conditions  which  must  be  consid- 
ered in  any  proposed  rolling  mill  drive,  it  has  been  shown  that : 

1 — The  electric  drive  is  absolutely  reliable. 

2 — Alternating  current  motors  and  transmission  system 
should  be  used. 

3 — A  frequency  of  25  cycles  per  second  is  preferable. 

4 — With  blast  furnace  gas  available  the  greatest  amount 
of  power  may  be  obtained  from  a  gas  engine  plant. 

5 — A  boiler  plant  with  steam  turbines  will  produce  three- 
fourths  the  power  obtainable  with  the  same  fuel  used  in  a  gas 
engine  plant. 

6 — The  great  reliability  of  a  steam  turbine  plant  outweighs 
the  excessive  power  obtainable  from  a  gas  engine  plant. 

7 — The  saving  in  investment  in  a  steam  turbine  plant  over 
a  gas  engine  plant  is  very  considerable. 

8 — It  is  more  economical  to  generate  electric  power  at  the 
source  of  gas  supply  and  to  transmit  same  to  motor  driven  mills 
than  to  burn  the  gas  under  boilers  at  the  mill. 

9 — The  electric  drive  is  the  most  economical  system  for 
every  case  excepting  where  coal  must  be  burned  under  boilers 
at  the  mill  and  in  this  case  approximately  double  the  power 
can  be  obtained  from  a  given  amount  of  steam  by  using  low 
pressure  turbines  in  the  exhaust  from  mill  engines. 

The  writer  believes  the  foregoing  conclusions  to  be  correct 
and  that  a  careful  investigation  on  the  part  of  any  steel  works 
engineer  will  prove  their  correctness. 



Paramount  to  all  other  considerations  in  the  solution  of 
the  innumerable  and  ever  changing  problems  of  the  construct- 
ing engineer  of  the  present  day  must  be  his  unstinted  regard 
for  maximum  safety,  reliability,  and  economy  in  each  and 
every  one  of  his  constructions.  Not  one  cubic  inch  of  excess 
material  can  he  afford  to  have  his  mechanism  or  structure 
carry  as  an  unnecessary  ballast,  in  order  to  conform  with  the 
principles  of  economy;  and  yet,  on  the  other  hand,  it  should 
not  lack  a  jot  when  the  reliability  of  the  device  and  the  safety 
of  the  users,  into  whose  hands  it  is  placed,  is  involved.  Every 
element  and  feature  entering  into  the  design  of  his  engineering 
proposition  must  be  based  upon  thorough,  practical,  and  sci- 
entific study  and  investigation.  He  must  feel  secure  in  his 
claim  that  every  dimension  in  his  design  has  its  good  and 
logical  "raisou  d'etre." 

Any  novel  type  of  engine,  boiler,  dynamo,  bridge,  etc., 
representing  a  successful  design,  must  primarily  be  strong 
enough  and  sufficiently  resistant  to  withstand  the  repeated 
strain  of  the  forces  acting  upon  it.  The  elastic  deformations 
of  all  or  any  of  its  composite  members  when  stressed  to  their 
greatest  loads  must  remain  within  the  confines  of  safety — i.  e. : 
within  the  elastic  limit  of  the  materials  of  which  they  are 
constructed.  The  choice  of  the  proper  allowable  factor  of 
safety,  in  each  and  every  case,  is  an  extremely  important  and 
vital  question  for  the  engineer  to  decide.  The  rule  of 
the  thumb  will  not  do  when  it  comes  to  the  proper  di- 
mensioning of  an  engine  or  bridge,  and  the  calculations 
for  the  correct  proportions,  dimensions  and  the  proper 
and  economic  distribution  of  the  different  materials  that  com- 
pose the  various  parts  of  his  structure  must  be  based  upon 
established  scientific  and  practical  facts.  Experience,  science, 
and  theory  must  be  the  guiding  factors  in  the  effective  elabo- 
ration of  all  bis  engineering  work,  each  reinforcing  the  other. 
The  safe  allowable  working  stress  in  one  specific  case 
may  be  one-half  to  one-fourth  of  the  ultimate  strength  of  the 
material,  and  yet  in  another  instance  conditions  may  be  such 
that  twenty  to  forty  would  not  represent  an  excessive 
value  for  the  safety  factor.  Then  again  there  are  times 
when  the  allowable  working  stresses  mav  not  be  of  sneh 
a  significant  moment  as  the  allowable  working  strains,  which 
then  shonld  form  the  basis  in  the  ealcnlations  for  the  deter- 

♦Instructor  in  Experimental  Ensnneerins\   Armour  Institute   of  Technology. 



[Jan.,  1911 

mination  of  dimensions  and  selection  of  proper  materials. 

We  frequently  meet  conditions  where  the  cross-sec- 
tional area  of  a  certain  member  of  a  structure  can  be  kept 
at  a  low  figure,  when  the  working  stress  only  is  kept  in  view, 
but  when  we  consider  the  corresponding  strain  induced  by 
this  stress,  we  may  find  that  the  deformation  of  this  single 
clement  in  the  mechanism  or  structure  may  have  such  an 
influence,  in  its  relationship  to  immediate  adjoining  members, 
that  it  may  not  only  nullify  its  own  function,  but  that  of  the 
entire  design. 

From  an  illustration  in  the   (London)   Engineer. 
View    of    Wreckage    of    Quebec    Bridge. 

To  illustrate  the  responsibility  of  the  engineering  pro- 
fession and  to  emphasize  this  fact  to  the  young  graduate 
about  to  enter  the  field  of  practical  endeavor,  let  it  suffice  to 
point  to  such  examples  as  the  collapse  of  the  Quebec  bridge 
over  the  St.  Lawrence  and  numerous  boiler  explosions. 

An  instance  that  came  to  the  writer's  personal  notice 
some  time  ago  where  he  was  called  upon  to  render  expert  tes- 
timony regarding  the  probable  cause  of  the  explosion  of  a 
steel  tank  that  had  been  designed  for  the  storage  of  com- 
pressed air  under  pressure  of  several    hundred    pounds  per 

Vol.  Ill,  No.  1]     THE  SAFETY  FACTOR:     DIETZSCH  105 

square  inch,  may  serve  to  illustrate  the  importance  of 
the  proper  regard  for  correct  calculations  in  the  strength  of 
the  design,  and  for  the  choice  of  the  right  materials.  The 
failure  of  the  tank  could  he  directly  attributed  to  the  weak- 
ness of  a  cast  iron  flange,  which,  instead  of  measuring  21/2" 
to  3"  in  thickness,  was  erroneously  considered  heavy  enough 
with  IV'  of  metal.  The  cost  of  this  blunder  on  the  part  of 
the  designing  engineer  was  the  serious  injury  of  several  work- 
men engaged  in  testing  the  tank. 

There  is  a  growing  tendency  among  many  engineers  of 
today  to  base  the  factor  of  safety  upon  the  actual  elastic  limit 
and  not  upon  the  ultimate  strength  of  the  material.  In  many 
cases  it  is  really  incorrect,  in  the  writer's  estimation,  where 
it  is  necessary  to  deal  with  alternating  stresses  at  frequent 
and  rapid  applications,  to  base  the  factor  of  safety  upon  the 
ultimate  strength,  because  it  is  an  established  fact  that  when 
stresses  exceed  the  elastic  limit  of  any  material  it  only  requires 
a  definite  number  of  these  applications  until  the  actual  failure 
is  reached. 


BY  R.  B.  HARRIS,  M.  E  * 

It  has  happened  that  several  minds  working  under  similar 
conditions  and  with  like  surroundings,  but  with  entirely  dif- 
ferent objects  in  view,  have  almost  simultaneously  reached  the 
same  conclusion.  Such  a  situation  seems  well  illustrated  in 
the  development  of  vacuum  cleaning  apparatus  so  com- 
monly known  and  quite  universally  applied  during  the  period 
in  which  the  same  principle  was  being  perfected  for  the  hand- 
ling of  ashes.  The  success  of  vacuum  cleaning  by  applying  air 
suction  with  provision  for  free  flow  of  air  to  carry  dust  was 
paralleled  by  the  success  of  conveying  ashes  in  similar  manner. 

The  difference,  however,  in  the  actual  design  of  the  appa- 
ratus for  two  so  widely  different  substances,  both  to  be  handled 
by  air,  required  ingenuity  along  different  lines.  In  vacuum 
cleaning  the  dirt  and  dust  to  be  carried  is  relatively  insignifi- 
cant in  weight  or  volume  and  the  necessity  of  making  the 
apparatus  light  and  portable  is  pre-eminent,  while  wear  of  its 
parts,  in  conveying  such  material,  is  inappreciable.  On  the 
other  hand,  in  handling  ashes,  the  weight  and  volume  to  be 
carried  is  the  first  consideration,  and  the  wear  and  tear  while 
conveying  such  material  demands  design  of  parts  of  unusually 
heavy  construction. 

It  at  once  appears  necessary  to  make  the  apparatus  for 
handling  ashes  so  heavy  that  possibility  of  portable  form  is 
out  of  consideration  and  such  apparatus,  therefore,  becomes 
stationary.  Ashes  also  are  ordinarily  produced  under  condi- 
tions of  fixed  or  stationary  character,  and  the  systems,  there- 
fore, may  readily  be  designed  to  serve  as  collectors  of  ashes 
from  various  points  to  one  place  of  final  accumulation  and 
disposition.  This  makes  the  design  of  pneumatic  ash  handling 
machinery  to  be  adapted  to  fixed— but  different — conditions  in ' 
every  plant  an  engineering  problem,  and  not  merely  a  piping 

The  GrECO  Pneumatic  Ash  Handling  System,  as  exclusively 
manufactured  by  the  Green  Engineering  Company,  is  typical  of 
the  development  of  applying  air  for  conveying  purposes.  In 
these  Systems  a  conveyor  pipe  is  located  convenient  to  ash 
pits,  where  ashes  from  furnaces  are  deposited.  In  this  pipe, 
ash  intakes  are  provided,  into  which  ashes  may  be  conveniently 

*Class    of    1902.      Superintendent    of    Construction,    Green    Engineering    Com- 
pany,   Chicago. 

Vol.  Ill,  No.  1]      ASH  HANDLING  SYSTEMS  :     HARRIS  107 

raked  or  shoveled.  A  continuous  air  suction  with  high  velocity 
air  current  entering  ash  intakes  is  maintained,  and  the  ashes 
are  thereby  readily  fed  into  such  openings.  The  conveyor 
pipe  is  continued  to  a  separator  and  accumulating  ash  tank,  in 
which  the  high  velocity  of  the  air  current,  bearing  the  ashes 
in  suspension,  is  suddenly  reduced  to  almost  no  velocity  by 
expansion  and  the  ashes  at  once  deposited  in  the  tank.  To 
further  facilitate  such  deposit,  the  ashes  are  subjected  to  a 
water-spray  just  before  entering  the  tank,  the  water  serving  to 
wet  the  ash  particles,  increasing  their  weight,  as  well  as  to 
attach  the  dust  of  suspension  to  the  larger  ash.  At  an  angle 
radically  opposed  to  the  angle  of  entry  of  ashes,  an  exhaust 
pipe  serves  to  withdraw  the  air  entering  the  tank  by  way  of 
its  connection  to  a  powerful  exhauster ;  in  fact,  the  exhauster 
produces  the  air  current  through  the  entire  system  and  its 
suction  on  the  tank  is  sufficient  to  produce  the  high  velocity 
in  the  conveyor  pipe  connected  thereto. 

Between  the  tank  and  the  exhauster  a  dust  collector  is 
placed  through  which  the  air,  separated  from  ashes,  must  pass 
in  a  somewhat  helicoidal  path.  More  particularly,  the  ar- 
rangement provides  for  imminent  contact  of  air  current  with 
water  surfaces  for  the  purpose  of  still  further  extracting  any 
particles  of  dust  which  may  not  have  been  deposited  in  the  ash 

The  exhausters  for  Pneumatic  Ash  Handling  Systems  vary 
widely  in  capacity  and  pressure,  depending  upon  the  amount 
of  ashes  to  be  handled,  and  length  of  conveyor  pipe  through 
which  the  requisite  air  must  be  drawn.  The  exhausters  are 
driven  by  either  engines,  turbines  or  motors,  depending  upon 
the  most  convenient  motive  power  available  in  the  plant  to  be 

The  Systems  are  built  in  various  sizes,  rated  by  the  amount 
of  ashes  to  be  conveyed  per  minute.  Thus,  for  example,  a  6" 
System  has  a  capacity  of  150  pounds  per  minute ;  an  8"  System, 
300  pounds ;  and  a  10"  System.  500  pounds.  Such  rates  of  con- 
veying ashes  are,  relatively  speaking,  enormously  greater  than 
possible  capacities  of  any  other  form  of  ash  conveying  appa- 
ratus. In  fact,  conveying  capacity  of  Pneumatic  Ash  Handling 
Systems  exceeds  the  ordinary  ability  of  one  man  shoveling 
ashes  under  usual  circumstances.  It  is  therefore  necessary  to 
arrange  the  intakes  convenient  to  the  pits  where  the  ashes 
accumulate,  in  order  that  the  possible  rate  of  handling  ashes 
into  intakes  may  be  such  as  to  permit  one  man  to  feed  the  full 
capacity  of  the  System. 

It  is  to  be  borne  in  mind  that  but  one  ash  intake  should 
be  open  at  any  one  time,  and  that  at  this  point  only  can  ashes 

Vol.  Ill,  No.  1]     ASH  HANDLING  SYSTEMS  :     HARRIS 

be  fed  to  conveyor  pipe.  This  condition  is  made  apparent  by 
considering  two  ash  intakes  open  at  the  same  time;  the  one 
farthest  removed  will  be  without  air  suction,  as  suction  will 
naturally  be  spent  at  the  opening  nearest  the  separator  tank. 
To  more  readily  insure  free  air  supply  to  the  System  at  all 
times,  the  farthest  extension  of  conveyor  pipe  is  left  open  by 
attachment  of  a  fitting  known  as  an  "Air  Intake."  This  does 
not  interfere  with  the  full  suction  at  any  other  opening  nearer 
the  tank,  and  at  the  same  time  permits  free  operation  of  ex- 
hauster set  during  the  interval  while  operative  is  passing  from 
pit  to  pit  and  all  ash  intakes  are  closed. 

The  necessity  of  restricting  the  ash  intakes  to  but  one 
opening  at  any  one  time  is  really  a  decided  advantage,  from 
the  standpoint  of  labor  required,  as  the  relatively  enormous 
carrying  capacity  of  these  Systems  makes  it  readily  possible 
to  handle  as  high  as  fifteen  tons  of  ashes  per  hour  with  one 
operator,  and  there  are  few  power  plants  in  which  the  ash 
accumulation  cannot  be  handled  by  one  man  in  ten  working 
hours.  It  is  customary  to  arrange  the  size  of  ash  pits  suffi- 
ciently large  that  the  ash  cleaning  periods  are  limited  to  the 
work  of  one  man.  On  account  of  the  convenience,  and  as  the 
labor  involved  is  not  objectionable,  ashes  are  usually  cleaned 
from  the  pits  successively  in  very  short  time,  and  often  by  the 
same  man  firing  the  furnaces. 

The  nature  of  ash  from  coal  differs  widely.  It  may  not 
be  generally  known  that  ashes  from  different  coals  may  vary 
in  weight  from  as  low  as  30  to  as  high  as  60  pounds  per  cubic 
foot.  Inasmuch  as  the  weight  of  ash  to  be  handled  by  air  in- 
fluences the  amount  of  air  required  to  float  the  ashes  in  the 
air  current,  it  is  apparent  that  for  ash  of  varying  weight  dif- 
ferent air  currents,  or  air  velocities,  or  really  air  density  must 
be  provided.  In  this  respect,  the  Systems  require  other  calcu- 
lations for  heavy  ash  than  for  light  ash.  Further,  the  air  cur- 
rent actually  established  throughout  the  System  is  dependent 
upon  the  suction  maintained  at  the  opening  farthest  away 
from  the  separator  tank.  As  the  suction  to  be  maintained  in 
any  pipe  line  with  air  current  moving  there  through  is  depend- 
ent upon  the  friction  of  the  air  current  through  the  pipe,  the 
length  of  conveyor  pipe,  as  well  as  the  number  and  nature  of 
obstructions  (such  as  bends  or  turns)  causing  additional  fric- 
tion loss,  will  enter  the  calculation  of  air  suction  to  be  fur- 
nished by  the  exhauster  set.  Thus,  the  weight  of  ashes  to  be 
handled  will  determine  the  relative  volume  of  air  to  be  ex- 
hausted, and  the  friction  loss  through  the  System  will  deter- 
mine the  amount  of  suction  required. 

The  power  consumption  of  engine,  turbine,  or  motor,  driv- 

110  THE    ARMOUR    ENGINEER  [Jan.,  1911 

ing  the  exhauster  will  then  depend  upon  the  volume  and  suc- 
tion produced  by  the  exhauster  as  illustrated  above.  In  some 
6"  Systems  15  H.  P.  is  sufficient,  whereas  the  same  size  System 
may  require  60  H.  P.,  if  the  latter  should  employ  an  extremely 
long  conveyor  pipe,  with  probably  several  elbows  or  bends. 
Similarly,  either  of  these  Systems  of  the  same  size  conveyor 
pipe  may  require  15  to  40  more  H.  P.,  if  intended  to  handle 
heavier  ash.  Corresponding  figures  for  8"  Svstems  may  involve 
from  30  to  100  H.  P.,  and  10"  Systems  from  50  to  150  H.  P. 

As  the  necessary  air  currents  for  floating  or  carrying  the 
ash  in  suspension  are  relatively  of  high  velocity,  the  effects  of 
turns  in  the  conveyor  pipe  at  once  become  of  considerable 
consequence.  The  ash  entering  the  System  immediately  trav- 
els toward  the  center  of  the  pipe  where  the  greatest  air  veloc- 
ity is  maintained,  on  account  of  the  least  retardation  by  skin 
friction  of  the  conveyor  pipe.  In  other  words,  the  ash  really 
does  not  touch  the  pipe  after  entering  the  air  current  and  while 
continuing  at  its  maximum  velocity.  That  such  is  the  case  is 
readily  understood  by  considering  the  ash  particles  as  having 
relatively  large  surface  on  which  the  air  may  impinge,  and 
therefore  at  all  times  ash  particles  are  affected  most  by  the 
air  current  of  greatest  velocity. 

However,  when  such  ash  laden  air  current  reaches  a  bend 
in  the  conveyor  pipe  the  heavier  ash  particles  are  projected 
forward  to  the  outer  surface  or  back  of  such  bend,  and.  at  their 
high  velocity  ashes  at  once  attack  this  surface  in  the  same 
manner  as  a  sand  blast  would  attack  any  surface  towards  which 
it  is  directed.  In  these  Systems  suitable  provisions  are  made 
for  replacement  of  such  backs  and  to  conveniently  and  cheaply 
repair  such  abrasions  of  the  fittings  occurring  at  each  bend  in 
the  conveyor  pipe.  These  fittings  may  readily  be  opened  by 
removing  hand-holes  on  the  inside  curvature,  giving  access  to 
the  back.  The  life  of  wearing  backs  is  dependent  on  the  veloc- 
ity required  in  the  System,  on  the  nature  of  the  ash,  and  the 
amount  of  ashes  handled,  and  may  vary  from  ten  days'  life  to 
two  years',  depending  upon  such  conditions.  In  any  event, 
the  cost  of  replacing  and  maintaining  such  wearing  backs  is 
insignificant  when  compared  with  the  savings  possible  with 
these  Systems  over  any  other  method  of  handling  ashes  and 
maintenance  of  apparatus  therefor. 

Inasmuch  as  the  disturbance  at  elbows  may,  under  some 
conditions,  be  continued  by  one  or  more  rebounds  of  ash  from 
wearing-back  to  pipe  immediately  beyond  the  fitting,  it  is  cus- 
tomary to  provide  short  lengths  of  pipe  directly  beyond  such 
fitting  for  convenient  turning  of  pipe  and  eventual  replacement. 

Inasmuch  as  the  conveying  capacity  of  these  Systems  de- 

Vol.  Ill,  No.  1]      ASH  HANDLING  SYSTEMS  :     HARRIS  111 

pends  on  the  velocity  established,  and  the  velocities  attained 
depend  on  the  suction  provided,  it  is  apparent  that  air-tight 
apparatus,  fittings,  and  connections  should  be  provided  and 
maintained  throughout,  as  any  leakage  between  an  ash  intake 
opening  and  the  separator  tank  will  at  once  decrease  the  suc- 
tion and  thereby  the  velocity  of  air  current,  and  also  decrease 
the  suspending  property  of  the  air  in  motion  at  point  where 
ashes  are  introduced  and  elsewhere  within  the  System.  Should 
decreased  velocity  result  for  some  reason,  viz.,  should  ashes  be 
fed  at  excessive  rates  (which  rates  then  would  be  beyond  the 
suspending  capacity  of  the  air  current),  a  tendency  for  ashes  to 
lag  would  result;  that  is,  the  effect  of  gravitv  would  exceed 
the  effect  of  velocity  contributed  by  the  air  current,  and  then 
the  ashes  tend  to,  and  would,  eventually,  lodge  in  the  bottom  of 
the  conveyor  pipe.  Establishing  the  proper  air  currents  for 
such  excessive  feeding,  or  decrease  in  the  rate  of  feeding  the 
ashes,  would  again  restore  the  velocity  needed  and  such  parti- 
cles would  be  picked  up  and  assume  the  necessary  velocity, 
passing  on  as  originally  designed. 

Wet  ashes,  having  much  greater  weight  per  unit  of  vol- 
ume, would  enter  the  System  under  the  same  circumstances  as 
ashes  heavier  than  those  capable  of  suspension  by  the  air  cur- 
rent provided  in  the  System.  Therefore,  wetting  ashes  and 
then  introducing  them  into  the  System  usually  deposits  them  in 
the  pipes,  and,  as  wet  ashes  will  stick  to  any  surface  even  after 
dried,  the  introduction  of  wet  ashes  is  impractical.  However, 
as  ashes  may  be  fed  hot,  or  even  on  fire,  into  the  System,  and  as 
all  ashes  are  quenched  by  the  spray  before  entering  the  tank, 
there  is  really  no  occasion  for  wetting  prior  to  feeding  into 
the  System.  Further,  as  ashes  do  not  require  reshovelmg  or 
rehandling,  causing  the  stirring  of  dust,  and  as  dust  from  first 
handling  is  at  once  drawn  into  the  System,  there  is  really  no 
desire  on  the  part  of  operators  to  expend  the  additional  labor 
of  wetting  ashes  down. 

The  operation  of  these  Systems  depends  only  on  an  engine 
or  motor  and  its  exhauster  as  the  entire  moving  machinery. 
These  are  both  conveniently  located  and  away  from  the  ashes 
to  be  handled,  and  may  be  housed  to  protect  them  from  the 
machinery  deteriorating  conditions  usually  existing  in  boiler 
rooms,  or  incident  to  the  handling  of  ashes.  The  simplicity  of 
the  moving  machinery  of  these  Systems,  and  particularly  its 
remoteness  from  the  point  where  ashes  are  accumulated,  greatly 
reduces  the  maintenance  cost  thereof,  and  always  readily  per- 
mits its  inspection  under  most  favorable  surroundings. 

As  the  ashes  are  drawn  into  the  System,  any  dust  occa- 
sioned is   at   once    drawn   away,    and   no    opportunity   exists 

Vol.  Ill,  No.  1]      ASH  HANDLING  SYSTEMS:     HARRIS  113 

for  gases,  steam  or  dust  to  arise  and  contaminate  the  surround- 
ings. The  work  of  the  operator,  therefore,  is  relatively  pleas- 
ant as  compared  to  usual  methods  of  handling  ashes.  Under 
these  conditions,  conspicuously  clean  boiler  rooms  and  sur- 
roundings are  some  of  the  attractive  features  contributed  by 
the  System. 

The  absence  of  moving  machinery  in  boiler  rooms  and  ash 
pits  has  made  this  System  most  desirable  when  compared  to 
ash  conveying  devices  of  any  other  type.  No  possible  danger 
can  confront  the  operator  while  feeding  ashes  into  the  conveyor, 
nor  is  it  necessary  to  risk  life  or  limb  in  lubricating  any  mov- 
ing parts,  so  common  in  other  systems  usually  involving 
parts  located  in  dark  or  inaccessible  places.  As  ashes  are 
finally  stored  in  sealed  tanks,  danger  from  fire  is  eliminated. 

In  the  description  of  the  System  I  have  mentioned  the 
provisions  for  angles  or  bends  in  the  conveyor  pipe.  These 
possibilities  adapt  the  System  to  almost  any  construction  of 
boiler  rooms,  as  the  conveyor  pipe  line  can  be  arranged  to 
avoid  conflict  with  other  apparatus  and  either  pass  around, 
above,  or  below,  where  no  other  system  is  possible.  The  ash 
storage  tank  may  be  located  either  inside  or  outside  of  the 
building,  wherever  most  convenient  to  final  discharge  by  grav- 
ity to  either  car  or  carts.  Suitable  valve  for  this  purpose  is 
attached  to  the  cone-shaped  bottom  of  the  separator  tanks. 

The  final  discharge  from  the  exhauster  set  is  ordinarily 
conducted  into  the  chimney  or  breeching  serving  the  furnaces 
or,  directly  into  the  atmosphere. 

The  piping  connections  to  water-spray  are  usually  located 
convenient  to  controller  operating  motor,  or  to  the  engine  throt- 
tle, as  the  starting  of  the  entire  apparatus  involves  only  the 
turning  on  of  the  engine,  or  motor,  and  opening  the  water- 

The  sizes  of  ash  storage  tanks  vary,  depending  on  disposal 
arrangements  peculiar  to  any  particular  plant.  Tanks  of  five 
tons  capacity  would  be  considered  small,  while  75  tons  capacity 
for  railroad  car  discharge  would  not  be  unusual. 

The  GECO  Pneumatic  Ash  Handling  Systems  above  de- 
scribed are  manufactured  and  installed  exclusively  by  the 
Green  Engineering  Company,  Chicago,  who  employ  a  staff  of 
engineers  for  the  calculations  and  design  of  this  apparatus.  It 
is  not  inopportune  to  mention  that  several  A.  I.  T.  boys  are 
among  these  engineers. 

BY  M.  B.  WELLS.* 

The  evolutions  performed  by  aviators  include,  among  the 
most  daring,  the  spiral  glides  and  quick  turns.  In  making  a 
spiral  glide  the  aviator  rises  to  a  height  of  probably  several 
thousand  feet  and  descends  in  a  spiral  path  either  with  the 
motor  running  or  with  the  power  shut  off.  The  speed  attained 
is  sometimes  very  great,  the  time  of  making  one  circuit  is 
short,  and  the  banking  of  the  machine  is  at  a  steep  angle. 
No  definite  data  is  obtainable  in  regard  to  the  speed  or  the 
time  of  a  circuit  in  these  glides,  but  in  quick  turns  made  in 
ordinary  exhibition  flights,  time  as  short  as  five  and  one-fifth 
seconds  has  been  reported.  A  speed  of  fifty  miles  per  hour  is 
not  unusual  in  ordinary  straight  flights,  and  this  speed  is 
doubtless  often  exceeded  in  the  downward  circular  flights. 

The  following  is  a  discussion  of  the  principal  stresses  ex- 
isting in  a  biplane  making  a  complete  circuit  in  five  seconds  at 
the  assumed  speed  of  fifty  miles  per  hour :    The  circumference 

5280  X  50 

of  the  circle  swept  bv  the  machine  will  be  X  5 

60  X  60 


—  367  feet,  and  the  radius  of  the  circle  will  be  

3.14    X    2 
==  58  feet. 

From  mechanics  we  have  the  centrifugal  force  of  a  body  of 
mass  M 

=  M 

where  a  is  the  radius  of  the  circle  in   feet  and  T  the  time 
in  seconds  during  which  the  mass  moves  around  the  circle. 
The  total  weight  of  the  machine  and  operator  is  about  1,200 
pounds.     Substituting    the   known   quantities   in    the    above 
formula  and  solving  for  the  centrifugal  force  it  is  found  to  be 

"Associate  Professor   of  Bridge  and   Structural   Engineering,   Armour   Institute 
of  Technology. 

Vol.  III.   No.  1]   AEROPLANE  STRESSES:   WELLS         115 

1200  X  4  X  3.14  X  3.14  X  58 

=  3420  pounds. 

32.2  X  5  X  5 

This  acts  horizontally  and  outward,  while  the  weight  of  the 
machine  acts  vertically  downward.    The  resultant  of  the  two  is 

[  (3420) *  +  (1200) ']  »./»  =  3624  pounds. 

The  cosine  of  the  angle  that  the  line  of  action  of  this  resultant 
force  makes  with  the  horizontal  is  3420/3624  =  0.94,  and  the 
angle  is  20  degrees. 

With  the  pressure  of  the  air  perpendicular  to  the  surfaces, 
and  sufficient  to  halance  the  above  resultant  force,  the  angle 
that  the  machine  must  make  with  the  horizontal  is  90° — 20°= 
70°.     Observations  and   photographs   of  machines   in   circular 


6-.o"           1           .S'-o'           !»,-°*[.           *°"         ,1-           «'-«'         r|,           «'■"'         J 

»                              <t                             OK                              FT                              4                              » 


TT-tc  Rrmour  £V 

Outline    of   Biplane    Truss. 

flight  indicate  that  under  extreme  conditions  they  approach 
such  an  angle. 

The  total  downward  and  outward  resultant  force  being 
3624  pounds,  each  pound  of  weight  of  the  machine  exerts  a 
force  of  3624/1200=3.02  pounds  along  lines  parallel  to  this 
resultant ;  that  is,  perpendicular  to  the  chords  of  the  main 
trusses  of  the  machine. 

The  accompanying  sketch  is  an  outline  of  one  of  the  two 
main  trusses  of  a  machine,  the  plane  of  the  truss  being  perpen- 
dicular to  the  line  of  flight.  For  convenience  it  is  placed  with 
its  longer  dimension  horizontal.  It  is  assumed  that  one-half  the 
weight  of  the  machine  is  distributed  over  this  truss  as  follows : 
At  each  of  the  points  A  and  a,  7V2  pounds;  at  each  of  the 
points  B,  b,  C,  c,  and  D,  15  pounds;  and  at  d  210  pounds.  The 
right  half  is  loaded  the  same.  Multiplying  each  of  these 
weights  by  the  constant  3.02  gives  the  pressure  exerted  at  the 
respective  points,  the  truss  being  now  turned  so  that  these 

116  THE    ARMOUR    ENGINEER  [Jan.,  1911 

pressures  are  vertical.  They  are  as  follows :  At  each  of  the 
points  A  and  a,  7.5X3.02  =  22.65  pounds;  at  each  of  the 
points  B,  b,  C,  c  and  D,  15  X  3.02  =  45.3  pounds;  and  at  d, 
210  X  3.02  =  634.2  pounds.  The  total  downward  pressure  on 
this -truss  is  then,  (634.2  +  5  X  45.3  -f  2  X  22.65)  X  2  =  1812 
pounds,  and  this  is  balanced  by  the  pressure  of  the  air  in  the 
opposite  direction. 

The  surfaces  are  5%  feet  wide,  and  the  total  area  support- 
ing this  truss  and  its  load  is  5.5  X  2  X  39  /  2  =  214.5  square 
feet.  The  pressure  per  square  foot  on  the  surfaces  is  1812/ 
214.5  ==  8.45  pounds.  The  number  of  square  feet  at  A  is 
(5.5/2)  X  3  =  8.25,  and  the  number  of  pounds  of  upward 
pressure  is  8.25  X  8.45  =  69.7.  The  upward  pressure  at  a  is 
the  same ;  the  upward  pressure  at  each  of  the  points  B,  b,  C,  and 
c  is  two  times  the  above  or  69.7  X  2  =  139.4  pounds;  and  the 
upward  pressure  at  D,  also  at  d,  is  (5.5/2)  X  (3  +  1.5)  X 
8.45  =  104.5  pounds ;  the  corresponding  upward  pressures  on 
the  right  half  being  the  same. 

The  differences  between  the  upward  and  downward  pres- 
sures at  the  respective  panel  points  of  the  truss  give  the  re- 
sultant loads  at  these  points  which  are  to  be  used  in  determin- 
ing the  stresses  in  the  truss  members.  At  A  the  resultant  load 
is  69.7  —  22.65  =  47.05  pounds  upward,  and  at  a  it  is  the 
same.  At  B,  b,  C,  and  c  the  resultant  is  139.4  —  45.3  =  94.1 
pounds  upward,  at  D  it  is  104.5  —  45.3  =  59.2  pounds  upward, 
and  at  d  it  is  634.2  —  104.5  =  529.7  pounds,  downward.  The 
algebraic  sum  of  these  upward  and  downward  loads  is  zero. 

All  diagonals  are  designed  to  take  tension  only.  Passing 
a  section  through  CD.  Cd,  and  cd,  and  taking  moments  at  d 
gives  the  following  equation : 

94  X  18  -f  188  X  (12  -f  6)  +  CD  X  6  =  0; 

CD  =  —846  pounds. 

This  is  also  the  stress  in  DE  and  EF.  The  stress  in  de  is 
the  same  but  of  opposite  sign.  With  the  same  section  and  the 
center  of  moment  at  C  gives  the  equation  94  X  12  +  188  X 
6  —  cd  X  6  =  0,  which  when  solved  gives  cd  =  +376  pounds. 
The  stress  in  BC  is  the  same,  but  with  opposite  sign.  With 
a  section  across  the  panel  ab  and  center    of    moments    at    b 

the  stress  in  AB  = =  94  pounds.    The  stress  in  be 

Vol.  III.  No.  1]   AEROPLANE  STRESSES:   WELLS         117 

is    +94  pounds,  and  the  stress  in  ab  is  zero.  » 

The  upper  portion  of  the  post  Dd  has  a  tension  equal  to 
the  upward  resultant  at  D,  or  59  pounds.  The  portion  of  the 
post  below  the  engine  connection  has  a  compressive  stress  of 
529  —  59  =  470  pounds.  Passing  a  section  cutting  BC,  Cc,  and 
cd,  the  forces  on  the  left  are  all  upward  and  are  equal  to 
2  X  47  +  3  X  94  =  376  pounds.  376  +  Cc  =  0.  and  Cc  = 
— 376  pounds.  Similarly  the  stress  in  the  post  Bb  is  — 188 
pounds,  and  in  the  post  Aa  it  is  — 47  pounds. 

The  vertical  component  of  the  stress  in  Cd  is  (2  X  47)  + 
(4  X  94)  =  +470  pounds,  and  this  multiplied  by  the  secant  of 
45  degrees  =  +470  X  1.41  =  +663  pounds.  The  stress  in  Be 
is  (2  X  47  +  2  X  94)  X  1.41  =  +398  pounds,  and  the  stress 
in  Ab  is  2  X  47  X  1.41  =  +133  pounds.  The  stress  in  the 
diagonals  of  the  panel  de  is  zero. 

In  these  results  the  plus  sign  has  been  used  for  tension  and 
the  minus  sign  for  compression  stresses. 

The  above  given  stresses  will  be  modified  when  the  planes 
of  the  main  trusses  are  not  approximately  perpendicular  to  the 
chords  of  the  curved  supporting  surface. 


BY  H.  W.  CLAUSEN,  C.  E.* 

During  the  years  1872-1874  a  circular,  brick-lined  water 
tunnel  of  7'  internal  diameter  was  constructed  by  the  city  of 
Chicago  from  the  present  old  two-mile  crib  to  a  point  near 
22nd  Street  and  Ashland  Avenue,  where  it  connects  with  the 
old  West  Pumping  Station,  now  called  the  22nd  Street  Pump- 
ing Station.  The  line  of  this  tunnel  runs  straight  from  the 
two-mile  crib  to  a  shaft  located  at  Chicago  Avenue  and  Lincoln 
Parkway,  just  outside  the  present  Chicago  Avenue  Pumping 
Station,  and  straight  from  this  shaft  to  a  shaft  located  just 
outside  the  pumping  station  at  22nd  Street  and  Ashland  Ave- 
nue. The  depth  of  the  tunnel  below  the  surface  varies,  but 
it  is  not  less  than  60  feet  at  its  highest  point.  This  straight 
tunnel  line  was  adopted  on  the  principle  that  the  hypothenuse 
of  a  triangle  is  shorter  than  the  sum  of  the  other  two  sides,  and 
of  course  on  this  proposition  the  cost  of  the  tunnel  was  re- 
duced. It  was  also  believed  justifiable  to  adopt  this  plan  of 
crossing  under  private  property,  because  it  was  supposed  that 
no  foundation  would  ever  be  carried  to  such  a  depth.  This 
reasoning,  which  was  sound  enough  at  the  time,  is  now  in- 
correct, because  foundations  for  our  large  buildings  are  now 
often  carried  down  to  rock,  which  may  be  as  far  as  120  feet 
below  the  surface. 

During  the  construction  of  a  pile  foundation  for  a  building 
in  another  part  of  the  city,  it  was  discovered  that  a  pile  had 
penetrated  one  of  the  city's  tunnels  which  luckily  happened 
to  be  only  a  connection  for  equalizing  purposes,  and  it  cost 
the  city  approximately  $120,000  to  have  the  damage  repaired. 
After  this  occurrence  it  was  made  a  rule  of  the  Building  De- 
partment, before  issuing  a  permit,  to  require  the  O.  K.  of  the 
City  Engineer  on  all  plans  showing  a  foundation  of  any  con- 
sequent depth.  In  1904  an  application  was  made  for  a  permit 
to  construct  a  commercial  office  building  on  a  pile  foundation 
on  the  south  side  of  Madison  Stret  and  on  the  east  bank  of  the 
Chicago  River.  Now,  when  this  was  referred  to  the  City  En- 
gineer it  was  discovered  that  the  tunnel  herein  described 
crossed  under  the  property  at  a  depth  of  about  sixty  feet  below 
the  surface.  The  permit  was  therefore  held  up  pending  an 
understanding  between  the   owner  and  the  city.     After  con- 

"Class   of  1904.     Assistant    Engineer,    City   Chief  Engineer's   Office,    Chicago. 

Vol.   III.  No.   1]   FOUNDATION  CONSTRUCTION:     CLAUSEN       119 

ferences  it  was  finally  agreed  between  the  parties  that  the  city 
should  build  a  caisson  foundation  for  the  building  and  pay  the 
difference  in  cost  between  the  pile  and  caisson  foundations, 
respectively.  Since  the  tunnel  in  question  was  the  only  source 
of  water  supply  to  the  southwest  side,  it  was  imperative  that 
no  damage  should  result  to  the  tunnel  as  a  consequence  of 

_L7ackso^  Blvd 

\  1/ 

^  ze- o."   Y 3'shcft 

these  operations;  therefore,  the  city  reserved  the  right  to 
let  the  contract  directly  and  supervise  the  construction  of  the 

Before  the  plans  could  finally  be  revised  to  show  the  lo- 
cation of  the  concrete  caissons  it  was  necessary  to  know  ex- 
actly where  this  tunnel  crossed  the  property.  Accord- 
ingly a  survey  had  to  be  made  connecting  various  working 
and  fire  shafts  along  the  line  of  the  tunnel.    This  survey  proved 

£ ! 


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Vol.  III.  No.  1]   FOUNDATION  CONSTRUCTION:     CLAUSEN       121 

to  be  rather  a  difficult  one  to  make  because  the  traffic  of  the 
downtown  district  made  progress  slow  and  frequently  dis- 
turbed the  set  up  of  instruments,  while  the  smoky  atmosphere 
made  sighting  difficult.  The  survey,  as  shown  in  Fig.  1,  was 
finally  completed,  however,  and  the  latitudes  and  departures 
calculated.  The  error  of  closure,  as  may  be  seen  from  the 
accompanying  table,  was  found  to  be  0.08',  or  one  inch,  east 
and  west;  and  0.06',  or  three-quarters  of  an  inch,  north  and 
south  .  Under  the  existing  conditions  this  was  considered  to 

-     Buildinc 


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Fig.   2.     Plan  of  Foundation   Caissons   for  Proposed   Commercial  Building. 

be  a  good  closure,  and  so  the  line  of  the  tunnel  with  reference 
to  the  building  lot  was  then  figured  .  The  foundation  plans 
were  next  completed,  as  shown  in  Fig.  2— the  caissons  along 
the  tunnel  being  planned  to  clear  the  outside  of  the  tunnel 
brick-work  by  at  least  three  feet.  The  soil  through  which  the 
tunnel  is  built  is  medium  stiff  blue  clay,  and,  as  the  internal 
hydrostatic  pressure  in  the  tunnel  was  about  20  pounds  per 
square  inch,  it  was  considered  necessary  to  make  the  excavation 
of  the  tunnel  caissons  from  a  point  8  feet  above  the  top  of  the 
tunnel  using  20  pounds  air  pressure.  The  other  caissons  were 
to  be  excavated  by  ordinary  means,  i.  e.,  under  atmospheric 
conditions.     The   column   loads   over   the   tunnel  were  to   be 



[Jan.,  1911 

supported  by  steel  box  girders  spanning  the  tunnel  and  were 
to  be  completely  surrounded  by  concrete. 

Work  was  commenced  on  a  number  of  the  common  cais- 
sons, the  tunnel  caissons  being  left  for  the  installation  of  the 
air  locks.  Caisson  No.  22,  the  first  tunnel  caisson  attempted, 
was  excavated  by  ordinary  means  to  a  depth  of  about  8  feet 
above  the  top  of  the  tunnel.    At  this  point  excavation  ceased 

and  an  air  lock,  constructed  about  as  shown  in  Fig.  3,  and 
located  as  indicated  in  Fig.  4,  was  installed.  After  the  air 
lock  was  ready  for  service  work  was  again  resumed  and  the 
excavation  carried  to  rock,  the  caisson  then  being  filled  with 
concrete  up  to  the  air  lock  under  air  pressure,  and  finally  to 
the  surface,  after  the  removal  of  the  air  lock.  In  order  to  ex- 
pedite the  work,  another  air  lock  was  constructed  for  use  in 
the  other  tunnel  caissons,  this  lock  being  different  from  the 

Vol.  III.  No.  1]   FOUNDATION  CONSTRUCTION:     CLAUSEN       123 

one  shown,  in  that  instead  of  bolting  the  top  hood,  as  it  were, 
to  the  lower  plate  securely  bedded  into  the  clay,  the  lock  con- 
sisted simply  of  plates  similar  to  the  lower  plate  of  the  one 
shown,  with  the  space  between  the  plates  being  lined  with 
the  usual  wooden  lagging  of  the  caisson.  This  latter  air  lock 
was  installed  at  about  the  same  depth  in  Caisson  No.  15  on  the 
opposite  side  of  the  tunnel.     When  the  excavation  under  air 

Fig.    4.      Typical    Construction    (with    Air    Pressure)    of    Caisson    Near    Tunnel. 

pressure  in  this  caisson  had  proceeded  to  an  elevation  corre- 
sponding to  the  springing  line  of  the  tunnel,  the  well  digger 
exposed  the  brick-work  of  the  tunnel  at  the  southeast  edge  of 
the  caisson  and  the  water  slowly  began  to  come  in.  He  im- 
mediately came  up,  and  the  well,  or  caisson,  was  allowed  to 
fill  up  with  water.  After  an  investigation,  during  which 
boring  holes  were  sunk  to  locate  the  tunnel,  it  was  found  that 
the  tunnel  was  located  3  feet  northwest  of  the  supposed  or 

124  THE    ARMOUR    ENGINEER  [Jan.,  1911 

surveyed  location,  and  that  the  caisson  in  question  had  ex- 
actly struck  the  tunnel  tangentially. 

It  may  here  be  stated  that  the  clay  soil,  through  which 
the  caissons  were  excavated,  was  full  of  sand  seams  and  sand 
pockets  so  that  often  the  air  pressure  would  suddenly  drop 
from  20  pounds  to  5  pounds,  this  creating  consternation  among 
the  engineers  in  charge.  This  unfavorable  circumstance, 
coupled  with  the  slow  and  cumbersome  method  of  progress, 
made  the  excavation  under  air  pressure  anything  but  popular. 
The  plans  were  accordingly  modified  so  that  the  caissons  on 
the  northwest  side  of  the  tunnel  were  moved  over  3  feet,  this 
necessitating  much  heavier  and  longer  box  girders  for  span- 
ning the  tunnel.  Due  to  the  fact  that  the  caissons  on  the 
southeast  side  of  the  tunnel  would  now  be  6  feet  instead  of 
3  feet  away  from  the  tunnel,  it  was  decided  to  sink  these 
caissons  by  ordinary  means,  except  that  in  passing  the  tunnel 
only  one-half  of  a  section  (or  21/£  feet)  should  be  excavated 
before  being  "lagged  up,"  the  usual  section  being  5  feet 
deep.  This  method  was  successfully  employed  on  all  the  cais- 
sons on  the  southeast  side  of  the  tunnel. 

It  may  be  of  interest  to  digress  for  a  moment  from  the 
subject  in  hand  and  relate  an  experience  in  one  of  these  cais- 
sons which  for  a  while  gave  the  writer  no  small  scare.  It 
was  about  1  a.  m. — the  writer  being  stationed  on  the  work 
for  twenty-four  hours  or  more  at  times  when  any  one  caisson 
was  being  excavated  past  the  tunnel,  and  the  excavation  in 
Caisson  No.  30  was  down  to  a  point  about  opposite  the  top 
of  the  tunnel.  It  had  taken  the  well  diggers  a  whole  shift  of 
8  hours  to  set  in  place  the  last  set  of  lagging  and  steel  rings, 
due  to  the  extreme  swelling  of  the  clay,  and  of  course  this 
caused  a  good  deal  of  apprehension  on  account  of  the  proxi- 
mity of  the  tunnel.  Now,  when  the  new  shift  of  well  diggers 
had  excavated  about  a  foot  below  the  lagging,  a  stream  of 
water  suddenly  broke  through  the  clay  with  great  force, 
striking  one  of  the  diggers  in  the  face.  The  men  were 
quickly  hoisted  up  away  from  danger,  for  it  was  supposed 
that  the  water  from  the  tunnel  had  broken  into  the  caisson. 
By  means  of  a  float  attached  to  a  steel  tape,  the  writer 
discovered  that  the  influx  of  water  diminished  instead 
of  increased,  finally  ceasing  when  there  was  about  10  feet 
of  water  in  the  caisson ;  this  proved  of  course  that  the  water 
had  not  come  from  the  tunnel.  After  an  investigatioL  it  was 
found  to  have  come  from  Caisson  No.  29,  which  was  only  4 
feet   east  and  which   had   been   excavated  and   concreted  up 

Vol.  III.  No.  1]    FOUNDATION  CONSTRUCTION:     CLAUSEN       125 

some  two  or  three  months  previous.  The  top  of  the  concrete 
in  this  caisson  was  about  14  feet  below  the  surface,  and,  being 
a  low  point,  rain  water  had  accumulated  in  it  to  a  depth  of 
about  10  feet.  When  Caisson  No.  30  had  reached  the  depth 
stated,  the  hydrostatic  pressure  from  this  water  was  sufficient 
to  break  through  four  feet  of  clay  and  drain  the  water  from 
the  higher  to  the  lower  level. 

For  the  caissons  on  the  northwest  side  of  the  tunnel  it 
was  decided  to  excavate  in  2%  foot  sections  as  before,  but 
to  employ  a  steel  shield  about  3  feet  long  with  a  cutting  edge, 
thus  leaving  no  exposed  excavation  at  all.  The  cutting  edge 
was  jacked  down  2%  feet  when  a  set  of  lagging  and  steel 
rings  would  be  inserted  inside  of  it  before  proceeding  with  the 
next  section.  This  method  was  carried  out  in  Caisson  No.  35 
but  was  found  to  be  so  slow  and  cumbersome  that  it  was 
abandoned  in  favor  of  the  others.  It  happened  in  Caisson  No. 
35  after  hard  pan  had  been  reached,  and  the  full  depth  of  the 
caisson  excavated,  that  while  it  was  being  belled  out  to  give 
greater  bearing  area,  water  broke  in  from  the  tunnel  and 
filled  it.  thus  making  it  necessary  to  concrete  it  under  water. 
This  leak  was  attributed  to  the  clay  drying  up  and  cracking 
as  a  result  of  the  long  exposure  to  the  air,  this  long  exposure 
being  necessary  when  using  the  shield.  The  shield  was  there- 
fore discarded  and  the  work  satisfactorily  completed,  except 
in  Caisson  No.  1,  by  means  of  2%  foot  sections  as  used  on 
the  southeast  side  of  the  tunnel.  In  Caisson  No.  1  water  came 
in,  as  in  Caisson  No.  35,  while  the  belling-out  was  in  progress. 
Due  to  this  technical  violation  of  the  contract,  the  owner  re- 
fused to  accept  the  foundation  as  built,  so  the  city  was  com- 
pelled to  purchase  the  lot,  which  it  still  owns  and  uses  as  a 
storage  yard  for  the  Bridge  Department.  Caisson  No.  15, 
where  the  tunnel  was  actually  struck,  was  filled  up  for  8  feet 
with  sand  and  cement,  in  bags,  and  then  with  clay  to  the 

This  unfortunate  circumstance  cost  the  city  a  good  deal 
of  money  and  so  it  was  decided  that  it  would  be  economy  to 
build  under  the  streets  belonging  to  the  city  another  tunnel, 
this  to  replace  this  old  cross-town  tunnel,  and  thus  avoid  any 
further  difficulties  with  foundation  construction.  This  was 
accordingly  done  and  the  Blue  Island  Avenue  tunnel  now 
has  replaced  it. 

It  was  the  good  fortune  of  the  writer,  about  a  year  ago, 
to  have  the  opportunity  of  walking  through  this  old  cross- 
town  tunnel  from  Van  Buren  and  Jefferson  Streets  to  Chicago 
Avenue   and  Lincoln  Parkway.     An  examination  showed  no 

126  THE    ARMOUR    ENGINEER  [Jan.,  1911 

cracks  and  no  traces  whatsoever  of  any  damage  done  to  the 
tunnel  at  the  point  where  it  was  encountered  in  Caisson  No.  15 
several  years  before.  This  inspection  also  revealed  the  fact 
that  the  fire  shaft  at  Market  and  Madison  Streets  was  off  the 
center  line  of  the  tunnel  by  about  2%  feet  to  the  southeast, 
which  accounted  for  the  error  in  tunnel  alignment  as  obtained 
from  the  survey.  It  seemed  a  pity  to  be  compelled  to  abandon 
this  old  tunnel,  because  the  examination  showed  a  perfect 
piece  of  work  in  an  excellent  state  of  preservation  after  40 
years  continuous  service.  The  line  and  grade  of  the  tunnel 
was  also  perfect,  and  the  depreciation  from  any  cause  what- 
soever, except  in  the  top  of  the  working  shafts,  was,  I  should 
say,  nothing. 

It  is  now  the  intention  of  the  city  to  use  the  property 
purchased  and  herein  discussed  as  the  site  for  a  large  central 
police  station  and  fire  engine  house. 


The  Semi-Annual  Technical  Publication  of  the  Student  Body  of 

VOL.  Ill  CHICAGO,  JANUARY,  1911  NO.  I 

Publishing  Staff  for  the  year  1911: 

C.  W.  Binder,  Editor. 

G.  H.  Emin,  Business  Manager.  L.  H.  Roller,  Assistant  Editor. 

M.  A.  Peiser,  Associate  Business  Manager. 

Board  of  Associate  Editors: 

H.  M.  Raymond,  Dean  of  the  Engineering  Studies. 
L.  C.  Monin,  Dean  of  the  Cultural  Studies. 
G.  F.  Gebhardt,  Professor  of  Mechanical  Engineering. 
E.  H.  Freeman,  Professor  of  Electrical  Engineering. 

Published  twice  each  year,  in  January  and  in  May. 

Publication  Office:     Thirty-third  St.  and  Armour  Ave.,  Chicago,  111. 


The  Armour  Engineer,  two  issues,  postage  prepaid $1.00  per  annum 

Single  Copies 50  cents 


Realizing  that  in  the  past  much  has  been  said  and  written 
in  an  effort  to  bring  to  the  attention  of  both  our  student 
and  alumni  bodies  the  aims  and  expectations  of  THE  ARMOUR 
ENGINEER,  we  hardly  believe  that  any  further  discussion 
or  information  regarding  the  scope  of  this  publication  will 
be  particularly  interesting  to  our  readers  at  this  time.  How- 
ever, we  now  wish  to  express  to  our  contributors  our  apprecia- 
tion of  their  painstaking  efforts  in  the  preparation  of  these 
articles,  for  we  feel  that  their  substantial  support  will  go  far 
toward  increasing  the  general  interest  in  our  magazine.  Also, 
for  the  benefit  of  those  who  still  expect  that  a  special  solicita- 
tion is  necessary,  we  want  to  repeat  the  now  standing  invita- 
tion to  all  Armour  men  for  contributions  to  our  columns  on 
any  of  the  engineering  topics  in  which  they  are  particularly 

128  THE    ARMOUR    ENGINEER  [Jan.,  1911 

In  the  article  appearing  in  this  issue  on  "Briquetted  Coal 
and  Its  Value  As  a  Railroad  Fuel,"  Mr.  Malcolmson  discusses 
a  subject  which  we  believe  will  prove  of  exceptional  interest 
to  our  readers,  it  being  so  closely  allied  to  the  present  and 
familiar  subject  of  conservation  and  development  of  our 
national  resources.  A  very  instructive  account  of  the  coal 
briquetting  industry  from  its  earliest  days  is  given,  together 
with  present  conditions  in  its  development;  the  article  conciud 
ing  with  a  summary  of  the  many  advantages  of  briquetted  over 
raw  coal. 

The  electric-resistance  furnace,  which  several  years  ago 
gave  the  graphite  industry  such  an  impetus,  is  now  rapidly 
being  extended  in  its  application  to  the  numerous  industries 
in  which  exceedingly  high  temperatures  are  required,  and  we 
have  from  Mr.  Badger  one  of  the  first  of  a  number  of  articles 
on  the  various  forms  of  these  furnaces,  together  with  an  ac- 
count of  their  applications  to  the  heating  of  different  metals 
and  other  refractory  substances. 

The  many  advantages  of  the  electric-motor  over  the  steam- 
engine  operation  of  rolling  mills  are  carefully  brought  out  in 
the  article  appearing  in  these  pages  on  "The  Electric  Driving 
of  Rolling  Mills."  In  this  discussion  is  also  contained  an  answer 
to  the  question  so  frequently  asked  by  those  not  very  familiar 
with  electrical  power  transmission,  as  to  the  advantages  of 
alternating  current  in  the  transmission  of  large  amounts  of 
energy  over  long  distances.  Another  item  of  particular  in- 
terest is  the  strong  argument  in  favor  of  steam  turbines  over 
the  gas  engines  as  the  prime  movers  for  the  generators,  al- 
though at  first  glance  it  would  seem  that  the  direct  conversion 
of  blast  furnace  gas  into  mechanical  and  then  into  electrical 
energy  would  be  more  economical  if  the  intermediate  genera- 
tion of  steam  were  not  involved.  However,  a  careful  con- 
sideration of  the  points  brought  out  in  Mr.  Dean's  article  will 
show  that,  everything  considered,  the  steam  turbine  has  a 
great  many  "talking  points," 

Vol..   111.     No.   1]  EDITORIALS  129 

The  Pneumatic  Ash  Handling  System  as  discussed  in  this 
issue  by  Mr.  Harris  offers  a  very  simple,  economical,  and 
comparatively  new  solution  to  the  problem  of  ash  handling  in 
present  day  boiler  rooms. 

Owing  to  the  rather  recent  development  of  this  system, 
the  calculations  entering  into  the  various  designs  have  not 
been  gone  into  until  they  shall  have  been  confirmed  by  data 
from  actual  tests ;  so  the  author  has  written  principally  on 
the  general  features  encountered  in  design  and  installation  of 
these  svstems. 

With  the  extremely  rapid  application  of  water  poAver  to 
the  production  of  electrical  energy,  there  has  grown  up  in 
recent  years  a  new  field  of  engineering  activity  in  which  the 
demand  for  trained  and  experienced  men  is  far  greater  than 
the  supply.  Realizing  this,  and  the  need  of  giving  to  the  tech- 
nical student  desirous  of  fitting  himself  for  work  in  this  sphere 
of  engineering  a  course  of  thorough  instruction  in  the  funda- 
mentals, as  well  as  in  many  of  the  details  in  the  successful 
design  and  construction  of  hydro-electric  plants,  there  is 
now  being  offered  at  A.  I.  T.  a  course  in  hydro-electric 
engineering.  As  this  name  indicates,  and  as  a  glance  at  the 
subjects  taught  confirms,  no  really  new  course  has  been 
created — simply  a  combination  of  subjects  from  the  hydraulic 
and  electrical  courses  effected. 

It  is  doubtful  if  many  of  the  hydro-electric  engineers  of 
today  ever  had  the  opportunity  of  pursuing  courses  of  study 
containing  a  combination  of  these  two  branches,  for  the  reason 
that  up  to  within  a  comparatively  few  years  very  distinct  lines 
have  separated  the  hydraulic  and  electrical  branches.  Now 
however,  we  see  in  the  hydro-electric  course  where  much  has 
been  done  toward  closing  the  gap  existing  between  the  two 
separate  courses  just  mentioned,  and  in  view  of  this  fact  be- 
lieve that  graduates  now  entering  this  field  of  work  are 
equipped  with  a  foundation  which  will  soon  enable  them  to 
hold  their  own  in  matters  of  design  and  construction. 

130  THE    ARMOUR    ENGINEER  [Jan.,   1911 

That  a  course  in  hydro-electric  engineering  should  be  es- 
tablished in  all  large  technical  schools  is  evidenced  by  the 
prejudice  and  suspicious  attitude  shown  toward  many  of  the 
proposed  hydro-electric  developments  of  the  present  day ;  and 
the  reason  for  this  existing  suspicious  attitude  may  be  attrib- 
uted largely  to  the  results  of  unintelligent  engineering  and 
management  on  the  part  of  men  who  really  are  not  quali- 
fied by  their  previous  training  and  experience  to  be  put  in 
charge  of  work  requiring  such  a  broad  training.  While 
there  are  comparatively  few  instances  of  absolute  failures 
which  can  be  laid  directly  to  the  miscalculations  of  the  en- 
gineers in  charge,  yet  there  are  many  instances  of  where  in- 
sufficient preliminary  investigations  and  calculations  have  per- 
manently reduced  the  efficiency  of  what  might  otherwise  have 
been  verjr  successful  power  developments. 

The  necessity  of  a  broad  insight  into  the  many  phases  of 
a  successful  development  of  our  water  power  resources  has 
been  mentioned,  and  in  an  attempt  to  show  this  we  might  add 
that  it  is  just  as  essential  for  an  engineer  connected  with 
hydro-electric  work  to  have  a  knowledge  of  the  legal,  financial, 
and  commercial  aspects  of  the  problem,  as  it  is  of  the  engineer- 
ing features.  In  fact  many  of  the  problems  of  design  and  con- 
struction admit  of  much  easier  solutions  than  do  those  in 
financial  and  commercial  matters,  and  the  ability  to  grasp  them 
will  often  settle  in  a  week  what  might  otherwise  take  the 
strictly  technical  man  years  of  investigation  to  determine  in 
regard  to  the  feasibility  of  a  given  project. 

This,  then,  would  also  seem  to  present  a  good  argument  in 
favor  of  even  more  instruction  than  is  now  given  the  technical 
student  along  the  lines  of  work  not  usually  supposed  to  enter 
into  the  work  of  the  engineer  and  yet  so  often  connected  with 
it ;  and  doubtless  when  engineers  become  more  familiar 
with  those  subjects  outside  of  their  own  sphere  much  will  have 
been  done  toward  giving  to  the  engineering  profession  the 
rank  among  other  professions  to  which  its  achievements  show 
it  is  entitled. 

Vol.   III.    No.  1]  ENGINEERING  SOCIETIES.  131 


The  Civil  Engineering  Society  is  today  the  most  pros- 
perous of  the  several  engineering  societies  here  at  school,  this 
being  due  in  part  to  the  interest  taken  by  the  upper  classmen 
of  the  Department  of  Civil  Engineering,  and.  in  part,  to  the 
co-operation  of  the  department's  faculty,  all  of  whom  are 
members — Prof.  Phillips,  Associate-Prof.  Wells  and  Assistant 
Prof.  Armstrong,  as  honorary  members,  and  Messrs.  Dean  and 
Penn  as  Senior  members.  The  active  membership  of  the  society 
at  the  present  time  is  about  fifty. 

Tbe  first  meeting  of  the  year  was  held  on  Tuesday,  October 
2o,  1910  in  the  Engineering  Rooms,  Chapin  Hall,  the  speaker 
of  the  evening  being  Dean  L.  C.  Monin,  whose  subject  was 
"Standards  of  Professional  Conduct."  Dean  Monin  especially 
emphasized  that  an  engineer  has  duties  to  four  parties — (1) 
his  client,  (2)  himself,  (3)  his  fellow  engineers,  and  (4)  the 
public.  The  several  codes  of  professional  ethics  now  adopted 
by  several  of  the  older  professions  were  mentioned,  and  the 
hope  expressed  that  the  engineering  profession  soon  adopt 
such  a  code.  The  necessity  of  membership  in  engineering  so- 
cieties was  discussed.  Dean  Monin  emphasizing  the  fact  that 
the  engineering  student  should  start  by  joining  the  society 
here  at  school  of  whatever  branch  of  engineering  he  was  par- 
ticularly interested. 

On  the  evening  of  November  8,  1910,  the  Society  was  ad- 
dressed by  Mr.  Henry  W.  Clausen.  Class  of  '04.  Assistant  En- 
gineer in  charge  of  pumping  stations  and  tunnels  for  the  city 
of  Chicago.  Mr.  Clausen  gave  some  "Hints  to  Young  En- 
gineers," and  in  his  talk,  as  well  as  later  by  answering  ques- 
tions put  to  him.  made  his  audience  acquainted  with  many 
practical  suggestions  and  short  cuts  on  the  job,  especially  as 
relating  to  street,  tunnel,  and  road  improvement  work. 

"Irrigation  in  the  West"  was  the  broad  title  of  Mr.  Frank 
A.  Coy's  talk  on  Tuesday  evening,  November  22,  1910.  Mr. 
Coy.  also  an  Armour  graduate  of  the  Class  of  1904.  has  re- 
cently been  engaged  in  work  on  several  irrigation  projects 
in  several  of  the  western  states.  The  reasons  for  these  proj- 
ects, preliminary  proceedings  necessary  to  get  them  under 
way.  the  methods  of  design,  and  actual  construction,  were  all 
taken  up  in  detail  and  discussed  by  Mr.  Coy. 

The  last  meeting  of  the  calendar  year  was  held  on  De- 
cember 6,  1910,  with  Mr.  George  H.  Bremner.  Engineer  of  the 
Illinois  District,  Chicago,  Burlington  &  Quincy  Railroad  Com- 

!32  THE    ARMOUR    ENGINEER  [Jan.,   1911 

pany,  as  the  speaker  of  the  evening.  His  subject  was :  "The 
District  Engineer  on  a  Eailroad:  His  Duties  and  How  He 
Performs  Them."  Mr.  Bremner  is  well  qualified  to  speak  on 
that  topic,  and  many  phases  of  a  District  Engineer's  work  were 
taken  up.  Organization  and  standardization  of  work  were 
especially  emphasized  as  being  essential  to  success  in  such  a 
position.  Blue-prints  of  various  C.  B.  &  Q.  R.  R.  Co.'s  stand- 
ard constructions  in  track  work,  construction  plans  for  their 
large  freight  yard  at  Galesburg,  111.,  and  plans  for  several 
bridge  sites,   were   shown.  ' 

A  new  feature  of  the  work  this  year  is  the  attempt  to 
interest  the  alumni  of  the  Department  of  Civil  Engineering 
in  the  society  and  its  work  by  keeping  them  posted  regarding 
its  meetings.  Many  of  them,  of  course,  cannot  be  reached,  but 
a  large  number  of  those  who  have  been  communicated  with 
have  accepted  the  invitation  to  attend  the  meetings.  This  is 
indeed  gratifying  and  it  is  to  be  hoped  that  this  interest  of  the 
alumni  will  continue  to  increase. 

O.     R.     ERICKSON. 


The  Armour  Institute  Student  Branch  of  the  American  So- 
ciety of  Mechanical  Engineers  has  progressed  thus  far  this 
year  with  pronounced  success,  meetings  being  held  on  the  first 
Wednesday  of  each  month.  While  it  is  desired  to  select  some 
talent  from  the  engineering  profession  at  large  to  lecture  at 
these  meetings,  the  main  purpose  of  the  society  is  to  call  upon 
its  members  for  papers  and  lectures  on  engineering  subjects, 
in  order  that  they  may  subdue  the  reluctant  attitude  often 
manifested  when  called  upon  to  speak,  and  to  acquire  the 
ability  to  lecture  in  public  without  hesitancy. 

The  "Annual  Smoker"  of  the  Society  was  held  in  October, 
and  the  first  lecture  given  in  November  by  Mr.  J.  C.  Peebles, 
whose  subject  was  "Simultaneous  and  Automatic  Control  of 
Coal  and  Air  Supply  to  a  Boiler  Furnace."  At  the  December 
meeting  Mr.  R.  B.  Ambrose  (member)  lectured  on  "Producer 
Gas  and  Some  of  Its  Methods  of  Manufacture."  Each  meeting 
was  attended  by  about  thirty-five  persons,  constituting  stu- 
dents and  members  of  faculty.  The  men  who  lectured  gave 
very  interesting  discussions,  and  the  society  feels  grateful  to 
them  for  their  efforts. 

On  January  4th,  1911,  Mr.  C.  E.  Sargent,  M.  E.,  of  Chi- 
cago, delivered  an  illustrated  lecture  on  "Gas  Engines."    The 

Vol.  III.    No.  1]  ENGINEERING  SOCIETIES.  133 

meeting  was  held  in  Science  Hall,  and  the  anticipation  of  a 
large  attendance  was  fully  realized.  Mr.  Sargent  easily  indi- 
cated that  he  is  a  pioneer  authority  on  this  subject,  and  for 
his  kindness  the  society  feels  very  thankful. 

The  present  membership  of  the  society  numbers  about 
twenty-five,  and  any  Junior  or  Senior  Mechanical  student  is 
eligible  to  membership.  The  local  society,  being  affiliated  with 
the  American  Society  of  Mechanical  Engineers,  renders  it  pos- 
sible for  the  members  to  procure  proceedings  of  the  above 
society  and  to  become  members  of  its  student  branch. 

C.   E.    BECK. 


Students  of  the  Chemical  Engineering  Society  are  very 
active  in  the  affairs  of  their  society  this  year  and  have 
taken  exceptional  interest  in  all  the  meetings  held  so  far.  The 
objects  of  this  organization  are.  of  course,  substantially  the 
same  as  those  of  all  engineering  societies;  namely,  to  create 
a  general  atmosphere  of  sociability  among  its  members,  and 
to  become  familiar  with  the  application  to  modern  chemical 
engineering  practice  of  those  principles  studied  in  the  class 

The  first  smoker  of  the  society  was  held  Wednesday,  No- 
vember 9th.  with  the  three  upper  classes  well  represented  and 
as  many  faculty  members  present  as  could  possibly  attend. 
During  the  evening  Professor  Tibbals  gave  a  short  talk  in 
place  of  Professor  McCormack,  who  was  unable  to  be  present; 
the  remainder  of  the  evening  being  spent  in  the  conventional 
smoker  style. 

The  first  regular  talk  before  the  society  was  given  by 
Mr.  F.  M.  De  Beers,  an  Armour  graduate  of  1905.  now  presi- 
dent of  the  Swenson  Evaporator  Company,  on  Thursday.  De- 
cember 8th.  Mr.  De  Beers  discussed  and  explained  the  many 
factors  entering  into  the  design  of  evaporators  for  various 
substances,  and  clearly  showed  that  this  work  requires  the 
services  of  men  who.  as  it  were,  are  a  combination  of  chemist 
and  mechanical  engineer,  a  combination  to  be  looked  for  in 
the  chemical  engineer. 

H.    SIECK. 

134  THE    ARMOUR    ENGINEER  [Jan.,  1911 


Recognizing  the  advantages  to  the  student  body  of  meet- 
ings for  the  reading  and  discussion  of  professional  subjects, 
the  Armour  Branch  of  the  A.  I.  E.  E.  was  organized  for  the 
reading  and  discussion  of  papers  as  published  in  the  "Trans- 
actions of  the  American  Institute  of  Electrical  Engineers," 
and  for  the  preparation,  presentation  and  discussion  of  orig- 
inal papers  by  members  of  the  organization  and  other  in- 

The  policy  pursued  so  far  this  year  has  been  to  have 
original  papers  presented  by  members  of  the  society,  believing 
that  the  new  members  would  feel  more  disposed  to  take  part 
in  the  discussion  of  the  subject  if  presented  by  a  fellow  student. 
The  remainder  of  the  school  year  will  be  devoted  to  papers 
presented  by  members  of  the  Faculty  and  practicing  engineers, 
thus  giving  those  of  the  society  who  complete  their  course  this 
year  an  opportunity  of  discussing  the  practical  side  of  en- 
gineering work  with  men  of  experience. 

The  Armour  Branch  held  its  first  meeting  of  the  school 
year  on  October  27,  1910,  at  which  Mr.  L.  L.  Williams  read  a 
paper  on  "Car  Lighting,"  in  which  he  pointed  out  the  ad- 
vantages of  electric  illumination  in  cars.  Following  this  came 
a  description  of  several  present  day  methods  of  car  lighting, 
after  which  the  advantages  of  the  "head  end,"  the  "axle- 
light"  and  storage  battery  systems  were  discussed.  The  main 
part  of  the  paper,  however,  took  up  and  explained  the  various 
parts  of  the  Bliss  system,  which  uses  a  generator  driven  from  a 
car  axle. 

On  November  17,  1?..,,  Mr.  G.  E.  Williams  read  a  paper 
before  the  society  on  the  "Otis  Electric  Elevator  Control." 
He  discussed  the  duties  and  early  development  of  electric 
elevatjrs,  and  by  means  of  slides  and  blue  prints  illustrated 
the  form  and  principle  of  the  Otis  control.  The  wiring  dia- 
grams were  traced,  the  operation  of  each  explained,  and  the 
merits  of  the  safety  appliances  discussed. 

Following  the  plan  of  the  society,  the  third  meeting,  held 
Dec.  15,  1910,  was  given  up  to  the  discussion  of  the  "Inter- 
poles  in  Synchronous  Converters,"  as  published  in  the  "Trans- 
actions of  the  A.  I.  E.  E."  The  subject  was  divided  amongst 
the  members  and  each  assigned  the  preparation  of  a  portion 
of  the  paper. 


Mr.  James  H.  Jacobson,  Engineer  Inspector.  Hoard  of 
Supervising  Engineers,  City  of  Chicago,  addressed  the  society 
January  5,  1911.  on  "Railway  Converter  Sub-stations."  By 
means  of  photographs  projected  on  a  screen,  Mr.  Jacobson 
explained  the  construction  and  equipping  of  sub-stations  from 
the  time  earth  is  turned  for  the  foundation  until  the  last  ma- 
chine has  been  installed. 

.7.    II.    FLETCHER. 




You  select  this  car  because  there  is  more  real,  honest  value  in  exchange  for  your 
money  than  you  will  find  in  any  other  car  on  the  American  market  today — 

The  Armour  Institute  of  Technology  one  of  the  greatest  schools  of  Engineering 
in  the  world,  purchased  a  19..1  Model  Halladay  40  H.  P.  chassis  after  an  exhaustive 
investigation,  because  in  their  judgment  the  Halladay  is  the  best. 

If  they  don't  know — who  does? 

The  Halladay  is  best  on  account  of  its  simplicity  in  construction,  accessibility  for 
repairs,  workmanship,  quality  of  material  and  flexibility.  What  more  — besides  a 
guarantee  insuring  you  of  the  protection  you  are  entitled  to?  Our  guarantee  is  the 
original — real  —  bonafide  guarantee— no  ifs — buts — providings  or  legal  jokers. 

GUARANTEE— READ  IT  Prof.  Gebhardt's  Letter-READ  IT 

Halladay  Motor  Company 

1421  Michigan  Avenue.  Chicago 

Mr Address 

We  guarantee  for  the  season   of   1911    Halladay 

Car  No Engine  No 

to  be  free  from  defective  material  and  imperfect 
workmanship.  We  also  agree  to  keep  this  car  in 
repair  and  proper  adjustment  without  cost  to  the 
owner,  providing  the  car  is  kept  properly  oiled 
and  supplied  with  a  sufficient  amount  of  water;  also 
that  the  owner  will  bring  to  us  this  car  for  our  in- 
spection at  least  once  each  month  during  the 

This  guarantee  does  not  cover  leaky  radi- 
ators, caused  by  water  freezing,  nor  any 
damage  resulting  from  accidents  or  abuse. 
It  is.  however,  understood  that  we  make 
no  warranty  whatever  regarding  pneumatic 
tires,  coils,  magnetos  or  batteries,  com- 
plaints regarding  which  must  be  taken  up 
with  their  respective  makers,  who  fully 
cover  the  same  with  a  sufficient  guarantee. 
Signed  the day  of 19 

Armour  Institute  of  Technology 

F,  W.  Gunsaulus,  President 

Oct.  19,  1910 
Halladav  Motor  Company. 

1421  Michigan  Ave..  Chicago.  111. 

Gentlemen:  —  In  reply  to  vour  favor  of  the  15th 
inst.  beg  to  state  that  the  Halladay  1911  "40" 
chassis  recently  purchased  by  us  is  to  be  used  in 
our  Mechanical  Engineering  Laboratory  for  ex- 
perimental purposes. 

A  number  ot  types  of  machines  were  examined, 
but  the  Halladay  1911  "40"  proved  to  be  the  best 
suited  for  our  purpose  on  account  of  its  simplicity 
in  construction,  accessibility  for  repairs,  flexibil- 
ity for  experimental  purposes  and  all-around  good 

The  machine  is  to  be  equipped  with  power, 
transmission,  absorption  and  traction  dynamo- 
meters, optical  power  indicator,  speed  indicating 
and  recording  devises,  special  apparatus  for  re- 
cording the  shock-absorbing  properties  of  the 
tires  and  springs — in  fact,  a  full  complement  of 
special  appliances  for  studying  the  action  of  all 
working  parts  under  various  conditions  of  opera- 
tions, Yours  very  truly. 

G.  F,  Gebhardt, 

Agents— If  you  expect  to  add  to  or  change  your  line,  do  it  now.    Nine    models,  $\  100 
to  $2650.  Manufactured  by  STREATOR   MOTOR  CAK  CO.,  Streator,  Illinois 


CHAS.  M.  HAYES,  President 

1431  Michigan  Ave.,  Chicago 

Calumet  2574 








MAY  1911 

COPYRIGHT,   1911 


G.  H.  EMIN 



MAY  1911 


By  STANLEY  DEAN,  C.  E.* 

The  Schaghticoke  Hydro-Electric  Development  of  the 
Schenectady  Power  Co.  is  located  on  the  Hoosic  River  at 
Schaghticoke,  N.  Y.,  twelve  miles  X.  E.  of  Troy.  X.  Y.,  and  22 
miles  east  of  Scheneetady.  X.  Y.  At  this  point  the  Hoosic 
River  bends  in  the  form  of  a  letter  ilS"  in  a  distance  of  about 
two  miles,  measured  along  the  stream,  and  in  this  length  it  has 
a  fall  of  approximately  150  feet.  The  stream  flow  and  head 
are  used  to  develop  20,000  H.  P..  a  small  part  of  which  is  used 
locally  for  lighting  and  motor  service,  but  the  greater  part  of 
which  is  transmitted  to  Schenectady. 

In  brief,  the  development  consists  of  a  solid  concrete  spill- 
way dam  built  diagonally  across  the  river  at  the  head  of  a 
series  of  falls  and  rapids,  and  an  intake  at  the  down  stream  end 
of  the  dam  leading  to  a  canal  2,300  feet  long  cut  through  earth 
and  rock,  ending  in  a  forebay  from  which  the  water  is  led  by 
means  of  a  circular  steel  pipe  across  a  bend  in  the  river  to  a 
circular  steel  surge-tank  on  the  opposite  bank. 

From  the  surge-tank  four  main  unit  steel  penstocks  each 
six  feet  in  diameter  and  one  exciter  penstock  two  feet  in  di- 
ameter, lead  to  four  5000  H.  P.  vertical-shaft  water-turbines 
and  to  two  horizontal  exciter  turbines,  respectively,  located  in 
the  power  house,  from  which  the  water  is  discharged  into  the 
river  below  the  foot  of  the  last  rapids. 

Each  of  the  four  main  units  consists  of  a  "Pelton-Francis" 
inward  and  downward  flow  type  of  reaction  turbine,  designed 
for  a  full  load  output  of  5000  H.  P.  at  300  R.  P.  M.  under  a 
head  of  146  feet,  and  mounted  on  a  vertical  shaft  directly  be- 
neath its  alternator.  Each  alternator  has  a  full  load  output  of 
3000  K.  W.  at  full  load  at  4100  volts.  For  transmission  to 
Schenectady  this  is  stepped  up  to  32000  volts. 

It  is  the  purpose  of  this  paper  to  describe  the  apparatus 
and  methods  used  in  tests  to  determine  the  efficiency  of  two 
of  the  main  water  turbines. 

Class    of    100r>.      Instructor    in    Civil    Engineering,    Armour    Institute    of    Tech- 


[May,  1911 

Fig.  1.     General  Plan  of  Schaghticoke   Plant   of  the   Schenectady   Power   Co. 

Vol.  III.  No.  12|    TURBINE   EFFICIENCY  TESTS  :    DEAN 

Previous  to  these  tests  an  attempt  had  been  made  to  meas- 
ure the  water  discharged  from  the  wheels,  by  means  of  a  sharp 
crested  weir  built  across  the  race.  Owing  to  the  shortness  of 
the  tail  race  however  it  was  found  that  an  accurate  result 
could  not  be  obtained  in  this  manner  on  account  of  the  eddies 
from  the  draft  tube  causing  a  varying  head  over  the  weir. 
After  various  methods  bad  been  tried  to  obtain  an  adjustment 
of  the  water  surface  to  eliminate  the  sources  of  error,  the  con- 
clusion was  reached  that  some  other  method  must  be  used.  At 
this  time  an  accomodating  flood  came  along  and  carried  off 
weir  and  gauges,  leaving  only  the  abutments  standing,  and 
thus  settling  that  method  of  testing.  It  was  then  decided  to 
install  a  pitot  tube  apparatus  in  the  penstock  feeding  the 
wheel  to  be  tested,  which  was  accordingly  done. 

Description  of  Pitot  Tube  Apparatus  for  Measuring  the  Velocity  in 
the  Penstock 

If  a  straight  tube  be  bent  at  the  end  to  form  a  right  angle 
and  the  tip  submerged  in  a  flowing  stream  and  so  pointed  that 
the  mouth  of  the  tip  is  directly  opposed  to  the  current,  the  wa- 
ter will  rise  in  the  upright  part  of  the  tube  to  a  height  above 
the  water  surface  which  is  theoretically  equal  to  v2/2g,  the  ve- 
locity head  of  the  stream.  If,  noAv.  a  pitot  tube  be  inserted  in  a 
pipe  containing  water  flowing  under  pressure,  the  mouth  of  the 
tip  being  parallel  to  the  axis  of  the  penstock  and  opposed  to  the 
direction  of  flow,  and  a  straight  pipe  be  inserted  in  the  edge 
of  the  penstock  so  that  its  mouth  is  normal  to  the  axis  of  the 
penstock  and  direction  of  flow,  water  will  rise  i?i  the  stem  of 
the  pitot  tube  to  a  height  of  h  -\-  v2/2g  equal  to  the  sum  of  the 
pressure  and  velocity  heads  in  the  penstock,  while  in  the  stem 
of  the  straight  tube  the  water  will  rise  to  a  height  of  "h" 
equal  to  the  pressure  head  in  the  penstock.  The  difference 
in  height  of  the  water  columns  in  the  two  stems  will  be 
eqval  to  v2/2g  and  will  represent  the  velocity  head  in  the  pen- 
stock at  the  tip  of  the  pitot  tube.  To  measure  a  head  of 
approximately  150  feet  it  would  be  necessary  to  have  a  ver- 
tical stem  150  feet  high,  but  we  may  confine  the  heights 
within  reasonable  limits  by  forcing  the  water  column  down, 
by  connecting  a  source  of  compressed  air  to  the  top  of  the 
tube.  This  was  done  in  the  test  (see  Fig.  2)  where  the  distance 
A-B  equal  v2/2g,  the  velocity  head  at  point  of  pitot  tube. 

At  a  point  on  the  penstock  about  thirty  feet  uphill  from 
the  elbow  at  rear  of  powerhouse,  shown  on  Fig.  5.  the  pitot 
tube  apparatus  was  installed  to  measure  the  velocity  at  stated 
points  in  the  cross  section  of  the  penstock.     The  apparatus 



[May,  1911 

(see  Fig.  2  and  Fig.  3)  consisted  of  two  duplicate  pitot  tubes, 
shown  in  detail  in  Fig.  6,  arranged  to  slide  horizontally  and 
vertically  through  stuffing  boxes  screwed  into  the  shell  of 
the  penstock,  and  so  graduated  that  the  point  of  the  pitot 
tube  could  be  set  at  any  desired  position  on  the  horizontal 
and  vertical  diameters  (see  Fig.  7)  of  the  penstock.  The 
stem  of  each  pitot  tube  was  of  brass  and  about  seven  feet 

Fig.  2.     Elevation  of  Gauge  Board,  Penstock,  Pressure   Tubes  and  Pitot  Tubes. 

long.  To  the  end  of  the  stem  was  securely  clamped  one  end 
of  a  flexible  hose  about  twelve  feet  long,  the  other  end  of 
which  was  passed  over  and  clamped  to  the  lower  end  of  one 
of  the  exterior  vertical  glass  tubes  shown  on  gauge  board  in 
Fig.  2,  the  vertical  pitot  tube  being  connected  to  the  glass 
tube  on  extreme  left  and  the  horizontal  pitot  tube  to  the 
one  on  extreme  right.  About  one  foot  uphill  from  the  pitot 
tube  cross-section,  eight  small  iron  pipes  were  tapped  in  to  the 

Vol.  Ill,  No.  21     TURBINE   EFFICIENCY  TESTS:     DEAN 


penstock  at  points  equidistant  from  each  other  around  the 
circumference,  i.  e.,  separated  from  each  other  by  45  degree 
angles,  and  bent  around  in  easy  curves  to  connect  by  short 
lengths  of  rubber  hose  to  the  eight  vertical  glass  tubes  on 
gauge  board,  numbered  1  to  8  on  Fig.  2,  between  the  pitot 
tube  gauge  glasses.  Each  of  these  eight  pressure  gauge  glasses 
and  two  pitot  tube  glasses  were  connected  by  rubber  hose  and 
iron   "tee"  sections   of  pipe   to   form   a  horizontal   header  at 

Figr.   3.      Section   and   Elevation   of  Gauge   Board,    Penstock, 
Pitot   Tubes. 

ressure   Tubes   and 

top  of  gauge  board.  One  end  of  this  header  was  connected  by 
rubber  pressure  hose  to  the  compressed  air  storage  tank  located 
in  the  power  house.  At  the  other  end  of  the  header  was  placed 
a  blowoff  cock  to  let  out  excess  compressed  air.  Pet  cocks 
were  placed  at  the  top  of  each  pitot  tube,  at  the  connection 
of  each  pressure  pipe  to  penstock,  and  at  the  base  of  each 
glass  gauge  tube  on  the  gauge  board.     One  pet  cock  was  also 



[May,  1911 

connected  in  between  the  header  and  compressed  air  hose 
to  admit  or  cut  off  the  air  pressure.  All  gauge  glasses  were 
securely  fastened  in  position  on  gauge  board  by  clamps  and 
screws.  Immediately  behind  the  gauge  glasses  and  forming 
the  background  of  the  board  was  pasted  a  sheet  of  cross  sec- 
tion paper  graduated  in  inches  and  tenths.  The  gauge  board 
was  mounted  on  a  timber  platform  and  securely  braced  into 
position  as  indicated  in  Fig.  3.  To  insure  true  position  of  the 
pitot  tubes  and  to  support  them,  planks  were  placed  parallel 
to  and  immediately  beneath  same.  These  planks  were  gradu- 
ated to  correspond  to  the  numbered  points  shown  in  Fig.  7.  In 
order  to  keep  the  point  of  pitot  tube  from  being  bent  down- 
stream by  the  flow  of  water  in  the  penstock,  2"x%"  iron  guides 

"TTv  f\rmaur  Fnoineer: 
Fig.    4.      Plan    of    Penstocks,    Surge    Tank    and    Power    House. 

at  right  angles  to  each  other  were  securely  bolted  together 
and  to  the  penstock  immediately  behind  the  line  of  travel  of 
the  pitot  tubes,  to  support  same.  The  detail  of  these  cross 
braces  and  guides  is  shown  in  Fig.  8. 

The  detail  of  the  tip  of  pitot  tube  shown  in  Fig.  6  is 
worthy  of  note.  The  tip  proper  was  of  brass,  three  inches 
long,  accurately  bored,  and  smoothly  finished  to  the  dimen- 
sions shown,  and  was  screwed  on  to  the  stem  of  the  pitot  tube. 
The  mouth  of  the  tip  was  14",  which  dimension  decreased 
to  3/32"  at  the  throat  and  then  enlarged  to  %"  again,  the 
inside  diameter  of  the  stem  and  glass  gauge  rods.  The  object 
of  this  contraction  at  the  throat  was  to  reduce  the  surging 
of  the  water  columns  in  the  glass  gauge  tubes  due  to  small 

Vol.  Ill,  No. 



changes  in  the  velocity  of  water  in  the  penstock  during  the 
test  periods  and  to  render  the  time  of  surge  the  same  for  hoth 
up  and  down  motions,  thus  enabling  the  observer  to  read  the 
gauge  with  greater  accuracy. 

Description  of  Apparatus  for  Measuring  the  Effective  Pressure  Head 
on  the  Turbine 

As  stated  in  the  brief  description  of  the  plant  at  the  be- 
ginning of  this  article,  the  water  was  led  from  the  impounding 
reservoir  by  means  of  a  canal  and  single  conduit  to  a  surge 
tank  in  which  it  was  allowed  to  rise  to  the  level  of  the  hydrau- 
lic gradient.  From  the  surge  tank  the  feeder  pipes  led  di- 
rectly to  each  unit  at  the  poAver  house.     The  effective  head 


The  f^fmowr  ^nairteer*. 
Fig.  5.     Vertical  Section,  showing  Penstocks,  Surge  Tank  and  Power  House. 

on  the  turbines  when  running  was  therefore  the  difference  in 
level  between  the  water  surfaces  of  the  surge  tank  and  tail 
race,  minus  the  loss  in  head  between  the  surge  tank  and  the 
entrance  to  the  scroll  case,  due  to  entrance  loss  at  connection 
of  feeder  penstock  to  surge  tank,  and  to  bends  and  friction  in 
penstock,  plus  the  velocity  head  of  the  water  at  the  entrance 
to  scroll  ease.  In  such  a  case  all  losses  in  the  scroll  case, 
guides,  vanes,  and  draft  tube  are  considered  as  the  hydraulic 
losses  in  the  turbine  unit  itself,  and  therefore  are  not  to  be 
deducted  from  the  effective  head  as  stated  above. 

If  we  measure  the  actual  pressure  head  at  the  entrance 
to  the  scroll  case  and  add  to  this  the  difference  in  level  be- 
tween the  point  of  measurement  and  tail  race,   we   have  the 


[May,  1!)11 

total  pressure  head.  Adding  to  this  the  velocity  head  at  this 
point — i.  e.,  at  the  point  of  measurement  of  pressure  head, 
we  obtain  the  total  effective  head  on  the  turbine.  This  method 
was  accordingly  pursued.  In  Pig.  9  is  shown  diagramatically 
the  location  and  relation  of  gauges  for  determining  the  pres- 
sure head  on  the  wheel.  At  two  points  in  the  tail  race  were 
located  ordinary  hook  gauges  with  their  zeros  set  accurately 
at  elevation  150.0.  The  gauge  reading  added  to  150.00,  thus 
gave  the  exact  water  elevation  of  the  tail  race  above  datum. 

Flexible  tt-ose 

T3r-3S5  Clamp 

"TKe   ^rmour   Fnoineer, 

Fig.   6.      Detail    of   Pitot    Tube. 

To  measure  the  pressure  head  on  the  scroll  case,  a  small 
iron  pipe  was  tapped  into  same,  near  the  center,  and  led 
to  a  vertical  "U"  mercury  gauge  and  connected  to  the  upper 
end  of  one  of  the  vertical  tubes  by  a  rubber  hose  clamped 
over  same. 

Between  the  upright  columns  of  the  gauge  a  steel  tape 
graduated  in  feet  and  tenths,  was  stretched  with  its  150.0- 
foot  mark  accurately  placed  at  elevation  165.0.     A  stop  cock 


shown  in  Fig.  9  near  point  of  connection  of  pipe  to  scroll 
case  controlled  the  admittance  of  water  under  pressure  to  the 
gauge  tubes.  Before  opening  the  stop  cock,  mercury  of  spe- 
cific gravity  of  13.54  was  poured  into  the  funnel  at  the  top 
of  the  gauge,  and  of  course  rose  to  equal  heights  in  the  paral- 
lel columns.  To  measure  the  pressure  head,  the  stop  cock 
was  then  cautiously  opened,  the  full  pressure  gradually  al- 
lowed to  depress  the  right  hand  column  and  correspondingly 
force  upward  the  left  hand  column.  By  reference  to  Fig.  9 
it  will  be  seen  that  the  difference  between  the  tops  of  mercury 
columns  "Z"  read  on  the  tape  represented  the  height  of  a 
column  of  mercury  that  just  balanced  the  transmitted  water 

^11  connections  with  g  botts 

The  F\ 

rmour  Trr> ameer. 

Figr.  1.  Cross  Seetior 
showing  Points  «i 

of   Penstock, 
i    Pitot    Tube 

Fig.     8.       Details     of     Cross     Braces 
and   Guides   fow  Pitot   Tubes. 

pressure  from  the  scroll  case  at  the  elevation  of  the  top  of 
right  hand  mercury  column.  Multiplying  this  difference  of 
level  "Z"  by  the  specific  gravity  of  the  mercury  (13.54) 
gave  the  height  of  the  hydraulic  gradient  above  the  top  of  the 
right  hand  mercury  column.  Add  to  this  height  (13.54  Z) 
the  reading  "Y"  and  we  have  the  height  of  the  hydraulic 
gradient  above  elevation  165.00.  Adding  this  reading  to 
165.00  we  have  the  elevation  above  datum  of  the  hydraulic 
gradient.  Subtracting  from  this  latter  elevation  the  elevation 
of  tail  water  we  thus  have  the  total  pressure  head  on  the 
turbine.  From  our  observations  with  the  pitot  tube  on  the 
penstock  we  obtain  the  mean  velocity  and  quantity  <>i'  water 



[May,  1911 

flowing  through  the  penstock  to  the  wheel.  Then  q  =  a^  = 
a  2v2,  where  q=  total  quantity  of  water  in  cubic  feet  per 
second,  a,1  =  area  of  penstock  at  point  of  velocity  measure- 
ment, a2  =  area  of  cross  section  of  scroll  case  at  point  of 
pressure  tap,  v,  =  mean  velocity  at  same  point,  v2  —  mean 
velocity  thru  scroll  case  at  point  of  pressure  tap.  The  velocity 
head  at  this  point  equals  v2/2g,  which,  added  to  the  total  pres- 

y(gX+r  Svr\ac e  m  5*->ra*Tanl*.  ^ 

<L  ^Scroll  Cns* 
(S.o  on  oaone 

^   fli-mour  Eoorii 

Fig.    9.      Diagraniatio    Sketch    showing    Position    of    Gauge*    for    Measurement    of 
Pressure    Head   on    Turbine. 

sure  head,  gives  the  total  effective  head  on  the  turbine.  The 
mercury  used  in  the  test  was  tested  carefully  by  the  refiners 
and  guaranteed  to  be  of  a  specific  gravity  of  13.54.  In  order 
to  make  sure  of  this  figure  the  mercury  column  was  checked 
at  the  beginning  and  end  of  each  day's  test  from  the  known 
static  head  on  the  wheel  when  same  was  shut  down  and  no 

Vol.  III.  No.  2]     TURBINE  EFFICIENCY  TESTS:    DEAN  149 

water  passing  through.  Id  this  case  there  was  no  velocity 
head,  and  when  the  other  turbines  were  shut  off  the  difference 
in  height  between  mercury  columns  multiplied  by  the  specific 
gravity  of  the  mercury  should  give  the  difference  in  elevation 
between  the  top  of  the  lower  mercury  column  on  the  right 
hand  and  the  surface  of  the  water  in  surge  tank.  Prom  care- 
ful levels  this  was  checked  and  the  specific  gravity  of  the 
mercury  found  to  be  correct  as  given  by  the  refiners/ 


Unit    No.    2.  Test    No.    4. 

Traverse    A    (Horizontal) 

Calibration  of  Pressure  Gauge  8  in  respect  of  the  average  readings  of  gauges 

No.        1        2        3       4       5       6       7       S 
—1    —4   —1   -4       0—6    +1       0 
8)— 1.5 

—.2  =  C 
Remarks. — Iu    calibrating    pressure    gauges    we    find    that    gauge    8    reads 
.2   high ;   therefore   we  add   .2   to   the   difference,   or  velocity   head,   which   gives 
us   corrected   difference,   or   corrected   velocity   head. 



(A— B) 

(A— B)±C 




feet  per 











2g[(A— B)±C] 

reading  in 

point  in 

head  in 

head  iu      W 


tube       Time 






19              1 :37 


.    51.40 


















56.  SO 
























































































1              1:51 






Table    1. 

Readings    and    Reductions    for    Horizontal    Traverse    4-A. 

150  THE  ARMOUR  ENGINEER  [May.  1911 

Method  r-| 

In  making  the  test  it  was  determined  to  divide  the  cross 
sectional  area  of  the  penstock  into  ten  parts  of  equal  area 
made  up  of  nine  concentric  rings  or  bands  and  one  central 
circular  area.  At  the  center  of  each  one  of  these  rings  read- 
ings were  taken  as  shown  in  Fig.  7,  thus  giving  nineteen  read- 
ings on  each  horizontal  and  vertical  traverse.  In  making 
readings  with  the  pitot  tube  apparatus  the  eight  pressure 
gauge  tubes  on  the  gauge  board  were    first    calibrated  with 


lnit    No-    ~-  Test    No.    4. 

Traverse   B    (Vertical) 

Calibration   of  Pressure  Osiim  1    in   r..<.,..,.t  t,.  ti ..Q.,.i!„  ,       * 

readings  or  gauges 


Gauge  1   in  respect  t< 

>  the  average 


1       2       3       4       5 

0        7        8 

0   —1    +1    —4   —1 

-6    +2    +1 

81— .8 

— .1   =  c 
Remarks.— In    calibrating    pressure    gauges    we    find    that    gauge    1    reads 
.1    high;    therefore   we   add    .1    to   the   difference,   or  velocity   head,   which   gives 
us   corrected    difference,   or   corrected   velocity   head. 



(A— B) 

(A— B)±C 




feet  per 











2g[(A— B)±C] 


head  in      yj- 

tuhe       Time 





1               1:52 



































9.  B0 



























58.  (X) 














































10               2:04 






Table   2.      Readings   and    Reductions   for   Vertical    Traverse   4- 

Vol.  Ill,  No.  2]    TUKBIXE  EFFICIENT  "V  TESTS  :    I  >EAN 

respect  to  the  pressure  tube  adjacent  to  the  pitot  tube  being 
used,  and  by  applying  a  correction  to  the  readings  of  this 
adjacent  pressure  tube  the  average  reading  of  the  eight  pres- 
sure gauges  was  obtained,  it  being  found  by  observation  that 
the  pressure  gauge  columns  rose  and  fell  together;  thus  the 
average  bore  a  constant  relation  to  this  adjacent  tube  column. 
The  observer  then  read  simultaneously  the  columns  Ph  and  S. 
if  the  horizontal  pitot  tube  was  being  operated,  or  Pv  and  1  if 
the  vertical  pitot  tube  was  being  operated.  Two  observers 
working   together   checked    each    other's    observations,   these 


?•■>••  ;: ■•■?•■•*•';  ■; f^.f~-fni: 

Fig.    10.      Plot   of   Discharge   Curve. 

being  called  to  two  recorders  who  cheeked  each  other's  fig- 
ures at  the  end  of  each  run.  The  recorded  readings  (A  —  B^ 
-|-C  gave  the  velocity  head  in  inches.  These  were  reduced  to 
feet,  and  the  velocity,  v=  V  2gH  =  V  2g  [(A  —  B)  +  C]  in 
feet  per  second,  calculated  for  each  of  the  nineteen  points 
on  the  horizontal  and  vertical  traverses.  Values  of  the  veloci- 
ties for  thirty-eight  separate  positions  of  the  pitot  tubes  were 

calculated  from  the  observations  of  each  run  at  a  given  load 
and  gate  opening.  Tables  1  and  2  show  in  detail  the  readiugs 
taken  and  reduction  of  "v"  for  runs  No.  4- A  and  No.  4-B, 



[May,  1911 


April  29-30,  gate  —  open,  load  2700  k.w.    In  connection  with  the 

foregoing  and  figures  No.  2  and  No.  7  these  tables  should  be 
self  explanatory. 

Calculation  of  Penstock  Discharge  "Q" 

In  order  to  obtain  the  quantity  of  water  "Q"  from  the 
pitot  tube  readings,  a  plot  (Fig.  10  )of  velocities  at  the  several 
points  on  the  horizontal  and  vertical  traverses  was  made,  using 
velocities  as  ordinates  and  areas  as  abscissae.  A  curve  was 
passed  through  the  nineteen  points  on  the  horizontal  and  ver- 
tical traverses  and  the  quantity  "Q"  determined  by  using 
a  planimeter  to  measure  the  area  below  the  curve,  which  evi- 
dently is  equal  to  2  av  between  the  limits  of  the  penstock 
sides,  or  the  total  quantity  of  water  flowing  in  the  penstock. 

Measurement  of  Head 

Throughout  the  test  runs  readings  were  taken  on  the 
tail  race  gauges  every  fifteen  minutes,  and  on  the  long  and 
short  columns  of  the  mercury  gauge  every  three  minutes,  the 
readings  in  both  cases  being  nearly  constant  throughout  each 
run.  Two  observers  checked  each  other  and  recorded  sep- 
arately at  each  point.  The  readings  for  test  runs  4-A  and  4-B 
are  shown  in  detail  in  Fig.  10. 




(b— a) 





Tail   Race 


































(4— A) 

Av.  9.60 






















Av.  9.61 



4A    = 

horizontal    tube 

9.60    x 


=    129.984 

Pressure    head    =    143.564 
Area    of    scroll    case    at    pressure    tap      = 

.7854   x    (4.67)2    =    17.13   sq.   ft. 

Table   3.      Gauge   Readings. 

Vol.  Ill,  No.  2]    TURBINE  EFFICIENCY  TESTS:    DEAN 

Calculation  of  Efficiency  for  Test  Run  No.  4-A 
From  Table  3: 

Difference  of  level  of  long  and  short  mercury  gauge  =      9.60 

Equivalent  water  column  =  9.60  X   13.54." =  129.984 

Difference  of  elevation  between  top  of  short  column 

and  tail  race    =    13.58 

Hp  =  total  pressure  head   =  143.564 

Area  of  scroll  case  at  pressure  tap. 


A  = =  .7854  X   (4.67)2  =  17.13  sq.  ft. 


Velocity  of  water  in  scroll  case  at  pressure  tap. 

Q  270.04 

V  = = =  15.82  ft.  per  second. 

A  17.13 

Velocity  head. 

H    — 




=  3.891  feet 


Total  effective  head  of  wheel  = 

Hp  4-  Hv  =  143.564  +  3.891  =  147.455. 
Theoretical  horsepower  = 

QWH  270.04  X  62.4  X  147.46 

4517.7  H.  P. 

550  550 

Hydraulic  efficiency  of  turbine  = 

Horsepower  on  turbine  shaft  3663 

Theoretic   horsepower  4517.7 

=  81.17c 



[May,  1911 

Run  No.  4-B  by  a  similar  procedure  gives  an  efficiency 
of  82.0%,  the  average  81.55  is  therefore  taken  as  the  efficiency 

of  the  turbine  for  —  gate  opening.    Fourteen  similar  test  runs 

12  80 

with  gate  openings  varying  from  —  to  full  gate  — ,  and  with 

80  80 

load  varying  from  200  k.w.  up  to  3750  k.w.  were  made  on  the 

test  of  unit  No.  2  and  six  test  runs  with  gate  openings  of  —  to 


—  and  loads  varying  from  2000  k.w.  to  3700  k.w.  were  made 
for  unit  No.  3. 






; j- 




















■  ■ 



























■  i 






i»— i— 












•-  — 





.  i. 















....;. . 

— - 

tr       = 



:     1     | 


4- ._ 

...  ..  ;... 



.  .:.. 







!  ■ 






— — 
















*-    ' 



















:  ' 



i  '" 

— j- 


















Fig.  11.     Efficiency  Curves  for  Turbines. 

Electrical  Measurements. 

In  order  to  insure  accuracy,  specially  calibrated  ammeters, 
voltmeters,  and  wattmeters  were  used  to  measure  the  power 
output  of  the  generators  during  the  tests. 

The  alternators  supplied  three-phase  current  at  4,400  volts, 
and  for  ordinary  measuring  purposes  current  and  potential 
transformers  with  reducing  ratios  of  160 :1  and  40 :1  re- 
spectively, were  connected  between  the  leads  from  the  alter- 

Vol.  Ill,  No.  21    TURBINE  EFFICIENCY  TESTS:    DEAN 


nators  to  the  bus  bars  and  the  standard  measuring  instruments 
on  the  switchboard.  For  test  purposes  the  specially  calibrated 
portable  testing  instruments  we  cut  in  between  the  trans- 
formers and  the  switchboard. 

"To  bus 



Fbwer  Facto 

itenfi  a  I  Trarvs-i-orr^  ?r  | 

l?ound    mstr-umervfts    are    on    sla"fe    panel 
5q-v&re   i n s"tV u orients  *are    portable   "t"«si"  metsrs 

lK^    F\rrr\our  -pr,pinfl># 

Fig.  12.     General  Scheme  of  Connections  for  Measuring  Electrical  Power  Output 

The  arrangement  of  instruments  is  shown  diagramati- 
cally  in  Fig.  12,  the  regular  instruments  on  the  switchboard 
being  shown  as  circles,  and  the  special  test  meters  as  squares. 
The  readings  of  the  wattmeters  were  used  from  which  to  cal- 
culate the  power  developed,  and  the  ammeter  and  voltmeter 
readings  used  for  a  check  on  same. 

To  illustrate  the  method  of  calculation  the  first  run  of  test 
No.  1  of  unit  No.  3  will  be  worked  out  in  detail. 

Wattmeter  177503 
As  read         As  corrected 
158.0  156.5 

155.0  153.5 

153.0  151.5 

162.0  160.5 

Wattmeter  159103 

As  read      As  corrected  Time 

158.0                 158.0  2:46 

157.0                 157.0  2:49 

157.0                157.0  2:52 

157.0                157.0  2:55 









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Vol.  Ill,  No.  2]    TURBINE  EFFICIENCY  TESTS:    DEAN 


Add  the  watts  across  the  two  legs  of  the  circuit : 

156.5  -f  158.0  =  314.5  watts 

153.5  +  157.0  =  310.5  watts 

151.5  +  157.0  =  308.5  watts 

160.5  +  157.0  =  317.5  watts 

314.5  +  310.5  +  308.5  +  317.5 

312.75  watts  (av] 

Since  the  current  transformer    has    a     reducing    ratio  of 
160  :  1  and  the  potential  transformer  of  40  : 1,  at  the  current 
used  as  shown  by  the  calibration  table  (Fig.  5),  the  meters  have 
1  1 

received  only of  the  current  and  —  of  the  voltage  of  the 

160.1  40 

alternator.     The  output  therefore  is  312.75  X  160.1  X  40  = 
2002.85  k.w. 

For  the  second  run  of  test  No.  1  the  output  is  similarly 
calculated  and  the  mean  of  the  two  results  gives  2007.68  k.w. 
as  the  average  output  for  test  No.  1. 

>-    i 

%  Load 

Fig.  13.     Efficiency  Curves  of  Generator. 

CO    CO    *#    OJ 

C.    OS    CI    05 
Ci    OS    03    OS 


Ratio  160 
Amp.      R 

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Vol.  Ill,  No.  2]    TURBINE  EFFICIENCY  TESTS:    DEAN  159 


=2691.26  H.  P.  on  switchboard. 


The  generator  is  rated  at  3000  k.w. 


66.92%  load  on  generator.  From  efficiency  curve  of  generator, 
(see  Fig.  13),  determined  at  factory,  we  find  95.32%  efficiency 
at  this  load.    Dividing  the  measured  output  in  k.w.  by  the  gen- 


erator  efficiency  we  get =  2823.40  H.  P.  output  of 


turbine  at  shaft. 

Since  the  wheel  is  rated  at  5000  H.  P., 




Dividing  this  output  by  the  theoretical  horsepower  of 
the  water,  we  have 


: =  81.28% 


efficiency  of  turbine  for  test  No.  1  at  56.5%  of  its  rated  loading. 

No.   of   Test                             No.  1          No.  2  No.  3          No.  4 

See.    Ft.    Water 208.708  277.43  307.43        274.055 

Effective    Head    146.81  146.16  145.42        145.48 

Theoretical    H.    P 3473.76  4597.12  5068.46  4520.09 

K.   W.    on   Sw.    B 2007.68  2824.095  3117.91  2793.415 

H.   P.   on   Sw.   B 2691.26  3785.65  4179.5  3744.52 

Generator    Eff 95.32          96.42  96.68          96.4 

B.  H.  P.  Turbine   2823.4  3926.21  4323.02  3884.35 

Efficiency    Turbine    81.28          85.405  85.30          85.935 

Per   Cent   Load    56.5            78.5  86.5            77.7 

Table  6.     Recapitulation  Sheet. 

Similar  calculations  for  each  test  at  the  several  loads  give 
the  respective  efficiencies  from  which  the  curve  of  Fig.  11  is 

Table  6  is  a  recapitulation  of  the  calculated  quantities  used 
to  calculate  the  efficiencies  of  the  respective  test  runs. 

No.  5 

No.  6 



















160  THE  ARMOUR  ENGINEER  [May,  1911 

Mr.  H.  B.  Taylor  of  the  I.  P.  Morris  Co.,  designed  the 
hydraulic  testing  apparatus  used  in  both  tests  and  had  general 
charge  of  same. 

In  the  test  of  unit  No.  3,  April  14-15,  1909,  Mr.  H.  P. 
Rust  represented  the  engineers,  Messrs.  Viele,  Blackwell  and 
Buck,  assisted  by  Mr.  C.  F.  Trumbo  and  the  writer,  in  charge 
of  the  installation  and  operation  of  the  electrical  and  hydrau- 
lic testing  apparatus  (respectively).  Mr.  0.  A.  Harberlin 
looked  after  the  interests  of  the  Pelton  Wheel  Co.,  which  fur- 
nished the  units  under  test.  In  the  second  test  of  April  29-30 
on  unit  No.  2,  Mr.  C.  F.  Trumbo  and  the  writer  represented 
the  engineers,  Viele,  Blackwell  and  Buck  and  conducted  the 
test  as  on  unit  No.  3. 

The  writer  is  indebted  to  Messrs.  M.  M.  Beck  and  C.  F. 
Trumbo  of  Viele,  Blackwell  and  Buck,  and  to  Mr.  H.  B.  Taylor 
of  the  I.  P.  Morris  Co.,  for  the  data  from  which  this  paper  is 




The  pyrometer  is  an  instrument  which  is  used  to  measure 
comparatively  high  temperatures,  such  as  would  be  found  in 
blast  furnaces,  muffle  furnaces  or  retorts,  reverberatory  fur- 
naces, and  in  gas- machines.  In  connection  with  the  first  three 
furnaces  mentioned,  the  blast,  muffle  and  reverberatory,  the 
pyrometer  has  been  used  for  some  time  as  an  aid  to  the  daily 
operations,  and  considerable  literature  has  been  written  about 
the  pyrometer  as  used  with  those  furnaces,  but  the  use  of  the 
pyrometer  in  the  daily  operation  of  gas  machines  is  hardly 
past  the  experimental  stage,  and  practically  no  literature  can 
be  found  upon  the  subject.  It  is,  therefore,  the  intention  of 
the  author  to  set  forth  some  of  the  observations  made,  and 
results  obtained,  in  the  daily  use  of  the  pyrometer  since  it 
was  first  installed  in  a  gas  machine  under  his  supervision ; 
namely,  since   September   1908. 

This  article  is  not  intended  to  be  a  purely  scientific  trea- 
tise on  the  subject  to  be  discussed,  but  one  which  will  be  of 
practical  value  to  the  man  in  charge  of  a  gas  plant,  essaying 
to  give  a  clearer  understanding  of  the  conditions,  and  tem- 
peratures found  in  water  gas  machines,  and  to  disclose  such 
improvements  in  the  operations  of  the  machines  as  have 
been  the  result  of  the  use  of  pyrometers.  Consequently,  in 
various  parts  of  the  paper  commercial  terms  which  arc  readily 
understood  by  men  in  the  gas  industry  may  be  used  instead  of 
a  scientific  expression  of  the  same  conditions. 

For  reasons  which  will  be  apparent  in  the  discussion  of 
this  paper,  the  class  of  pyrometers  most  adaptable  to  our  use 
is  the  thermo-electric  pyrometer,  consisting  of  a  thermo-elec- 
tric couple  or  fire-end,  a  temperature  indicator  and  a  tempera- 
ture recorder  connected  in  parallel  to  the  fire-end  by  copper 
wire.  The  principle  upon  which  the  electric  pyrometers  are 
built  depends  upon  the  fact  that  when  two  wires  of  unlike 
metallic  composition  having  differing  electrical  conductivity  are 
welded  or  twisted  together  at  one  end  and  this  end  is  subjected 
to  heat,  a  difference  in  potential  is  set  up  in  the  cool  ends  of 
this  thermo-electric  couple.  If  these  ends  are  connected  by  cop- 
per wire  an  electric  current  is  established  through  the  wire. 
traveling  from  the  point  of  high  potential  to  the  point  of  low 
potential,   and   when   a   milli-voltmeter    (or   galvanometer)    is 

-(•Paper   read    at   the    Seventh    Annual   Meeting   of  the   Illinois   Gas   Association, 

Chicago,   March   15-16,   1911. 
♦Class  of  1907.     Asst.   Supt.   Testing  Laboratories,   People's  Gas  Light  &   Coke 

Co.,  Chicago. 

162  THE  ARMOUR  ENGINEER  [May,  1911 

placed  in  the  circuit  the  strength  of  the  current  may  be  ac- 
curately measured.  When  two  instruments  are  placed  in  par- 
allel so  as  to  read  the  temperature  from  a  single  fire-end  of 
thermo-electric  couple,  one  instrument  (for  example,  the  indi- 
cator used  by  the  gas  maker)  is  a  milli- voltmeter  and  the  other 
instrument  (such  as  the  recorder  in  the  superintendent's  office) 
is  a  galvanometer. 

The  strength  of  the  current  is  proportional  to  the  differ- 
ence in  potential  set  up  in  the  thermo-electric  couple  and  this 
difference  in  potential  is  proportional  to  the  difference  in  tem- 
perature of  the  hot  and  cool  ends  of  the  couple.  Hence,  if 
the  cool  ends  are  kept  at  a  constant  temperature  the  readings 
on  the  milli-voltmeter  and  on  the  galvanometer  will  be  di- 
rectly proportional  to  the  temperature  of  the  twisted  or  welded 
ends.  By  proper  calibration  of  the  two  instruments  they  may 
be  adjusted  to  read  directly  the  temperature  of  the  hot  June- 


Thskmo  -  Electric  Couplc      J  Indicator.  CfiCORPfiR 

tion  in  degrees  Fahrenheit  or  in  degrees  Centigrade.  It  is 
readily  seen  that  the  two  wires  of  the  fire-end  must  be  insu- 
lated from  each  other  to  avoid  the  danger  of  partial  short  cir- 
cuits due  to  the  difference  in  potential  of  any  portion  of  the 
wires  which  may  be  cooler  than  the  welded  end.  The  wires 
of  the  thermo-electric  couple  may  be  made  of  various  metals 
depending  largely  upon  the  temperatures  to  which  the  couple 
is  to  be  subjected,  although  as  a  rule  one  wire  is  a  single  metal 
and  the  other  is  an  alloy,  such  as  the  platinum  and  platinum- 
rhodium  couple,  the  iron  and  copper-manganese  couple  or  the 
nickel  and  nickel-chromium  couple.  The  composition  of  the 
gas  which  surrounds  the  couple  has  no  influence  on  the  indica- 
tions of  the  instruments. 

The  purpose  of  the  pyrometer  in  the  gas  machine  is  pri- 
marily to  aid  the  operator  in  maintaining  uniform  tempera- 
tures ("heats,"  according  to  work's  parlance)  in  the  various 
parts  of  the  machine,  at  the  best  temperature  for  making  gas 
of  a  desired  quality ;  and  secondarily,  to  keep  the  general  su- 
perintendent in  touch  with  the  operations  of  each  gas  maker 
on  both  day  and  night  shifts,  as  shown  by  the  recorder  instru- 
ment. The  object  of  this  paper  may  be  divided  into  the  follow- 
ing classification: — 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:     HEATH 


1.  A  determination  of 

a.  the  most  efficient  temperature  to  maintain  in  man- 

ufacturing gas  of  certain  quality. 

b.  the  effects  of  carrying  other  temperatures. 

c.  the  range  of  temperature  that  is  practicable. 

d.  the  limitation  of  theoretic  operation  by  practical 

2.  Illustration  of  a  method  of  installation  of  the  pyro- 
meter, so  that: 

a.  the  superintendent  while  at  his  desk  in  the  of- 

fice may  always  be  in  touch  with  the  operations 
of  the  gas  makers. 

b.  the  gas  makers  may  readily  watch  and  control 
the  temperatures  in  various  parts  of  the  ma- 
chine without  leaving  the  operating  valves. 

3.  A  determination  of  the  exact  temperature  in  various 
parts  of  the  machine  while  in  operation  in  order  that  we  may 
have  a  clearer  and  more  accurate  understanding  of  gas  ma- 

4.  An  exemplification  of  features  other  than  the  temper- 
atures of  operation,  whereby  the  use  of  a  pyrometer  has  been 
of  benefit  in  practice. 

5.  A  discussion  of  the  results  obtained  and  of  subsequent 
improved  methods  of  operating  the  machine  which  are  pri- 
marily due  to  the  aid  of  pyrometers,  in  such  a  manner  as  will 
be  of  interest  to  the  average  gas  man  and  will  aid  him  in  an 
understanding  of  machine  operations  even  if  he  has  no  inten- 
tion of  using  a  pyrometer  in  his  plant. 

Before  discussing  the  question  of  temperatures  most  suit- 
able for  the  proper  and  practical  operation  of  gas  machines 
it  may  be  well  to  describe  a  few  of  the  ordinary  conditions 
and  troubles  encountered  before  the  pyrometer  was  used.  At 
that  time  the  gas  maker  was  required  to  go  down  stairs  to 
the  floor  below  the  charging  floor  and  walk  around  his  ma- 
chine (in  the  case  of  type  No.  2)  or  to  climb  up  two  flights  of 
stairs  and  walk  around  his  machine  (in  case  of  type  No.  1)  to 
sight-holes  where  he  might  look  into  the  machine  and  judge 
whether  the  brick  were  too  hot  or  too  cold;  or,  whether  the 
oil  spray  in  the  carbureter  was  working  properly  or  was 
causing  "dark  streaks"  through  the  checker  brick.  It  will 
be  readily  seen  that  the  operator  could  not  make  this  trip  very 
often  and  attend  to  other  necessary  work,  such  as  proper  ad- 
justment of  primary  and  secondary  blast  valves,  regulations  of 
steam  pressure  and  of  oil  admitted  to  the  carbureter  within 
the  limited  time  of  these  operations.     Very  often  it  is  impos- 



[May.  1911 

sible  for  the  foreman  to  watch  the  temperatures  in  each  ma- 
chine, as  he  has  many  other  duties  which  demand  his  constant 
attention.  It  may  be  noted  that  in  stating  the  fact  that  the  gas 
maker  would  judge  the  temperature  of  the  brick  the  word 
"judge"  was  selected,  for  the  eye  may  be  deceived  in  many 
ways  as  to  the  true  temperature  of  brick  surrounded  by  a  gas 
or  gaseous  vapor  and  judgment  at  its  best,  we  all  know,  is  sub- 
jected to  the  personal  equation.  If  one  authority  would  say  a 
machine  was  too  cold  and  another  would  say  it  was  too  hot, 

Plate    1.      Pyrometer    Indicators    in    Generator    House. 

(Instruments  are  located  in  the  center  of  the  picture  between  the  gas  maker's 
desk  and  the  gauge  hoard — the  upper  one  for  the  superheater  and  the 
lower   for   carbureter.) 

what  should  an  ordinary  gas  maker  do?  There  is  no  personal 
equation  to  a  pyrometer,  and  as  previously  stated,  it  indicates 
the  true  temperature  irrespective  of  the  surrounding  gases. 

Before  the  instruments  were  installed  the  life  of  the  ma- 
chine was  from  800  to  1000  hours,  due  to  the  formation  of  lamp- 
black in  the  superheater.  The  checker  brick  would  often  be- 
come so  thickly  coated  with  carbon  that  the  resultant  back 
pressure  would  decrease  the  amount  of  gas  made  to  a  marked 
degree,  often  the  machine  had  to  be  shut  down  for  two  days 
at  a  time  in  order  to  burn  out  some  of  the  carbon  by  admitting 
air  through  the  checkering  doors.    When  the  machine  was  let 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:      HEATH 

down  for  repairs  the  bricks  would  be  covered  with  carbon  and 
ash,  burned  so  hard  as  to  require  a  pick  or  sledge  and  bar  at 
times  to  remove  them  from  the  upper  part  of  the  superheater. 
Strict  attention  to  the  temperatures  carried  in  the  operating 
machine  and  every  other  known  precaution  were  employed  to 
overcome  these  conditions,  but  without  results,  until  the  pyro- 
meter told  the  story.  The  condition  that  the  pyrometer  re- 
vealed will  be  discussed  and  illustrated  in  the  following  par- 

Upon  the  introduction  of  pyrometry  in  the  gas  industry 
in  Chicago  we  found  that  there  were  three  points  to  be  con- 
sidered in  placing  the  instrument ;  first,  the  best  position  of 
the  fire-ends  in  the  machine;  second,  the  most  accessible  posi- 
tion of  the  indicating  instrument  for  the  gas  maker;  and  third, 
the  most  desirable  position  of  the  recording  instrument  for 
the  superintendent.  It  was  necessary  to  have  two  sets  of  fire- 
ends  in  each  machine  to  control  the  temperatures  properly,  one 
in  the  carbureter  and  one  in  the  superheater.  The  carbur- 
eter temperature  was  taken  from  the  lower  part  of  the  car- 
bureter while  the  superheater  was  taken  from  top.  which 
at  that  time  was  considered  to  be,  and  was,  usually,  the  hot- 
test part  of  the  machine.  The  two  indicator  instruments  (one 
for  the  carbureter  and  one  for  the  superheater)  were  placed 
directly  in  front  of  the  gas  maker's  stool  and  beside  the  gauge 
board,  as  is  illustrated  in  Plate  No.  1,  and  connected  to  the  fire- 
ends  by  two  copper  leads  90  feet  in  length.  The  recorder  in- 
struments for  the  various  machines  Avere  placed  along  the  wall 
in  the  superintendent's  office,  as  illustrated  in  Plate  No  .2, 
and  connected  in  parallel  with  the  indicator  instrument  to  the 
fire-ends  by  copper  leads  600  feet  in  length,  which  fact  illus- 
trates the  adaptability  of  the  thermo-electric  pyrometer.  By 
this  arrangement  the  gas  maker  can  watch  the  temperature 
rise  or  fall  at  all  times  without  leaving  his  operating  valves. 
He  can  therefore  regulate  his  primary,  secondary  and  super- 
heater blast  valves  as  conditions  demand,  instead  of  operating 
by  a  "rule  of  thumb"  method.  The  superintendent  by  simply 
turning  in  his  chair  is  in  constant  touch  with  the  generator 
house.  He  can  tell  at  a.  glance  which  machine  is  down  for 
cleaning ;  how  long  each  has  taken  to  clean ;  how  the  cleaning 
time  compares  with  the  record  of  previous  days ;  what  temper- 
ature is  carried  by  each  machine  in  operation  during  the 
present  run  and  for  any  previous  run;  which  machines  may 
not  be  in  operation  and  how  long  they  have  been  shut  down; 
what  temperatures  were  carried  during  the  night  shift;  and 
how  long  a  machine  has  been  down  for  repair  work.     The  re- 


[May,  1911 

cording  chart  may  prove  of  value  in  case  of  dispute  as  to  the 
exact  time  an  accident  had  happened  on  a  machine  and  the 
length  of  time  required  to  make  repairs,  especially  if  the  oc- 
currence was  during  the  night  shift. 

When  the  first  instrument  was  installed  at  Pitney  Court 
Station  the  temperature  at  the  bottom  of  the  carbureter  was 
not  carried  as  uniformly  as  we  now  carry  the  temperatures. 
(See  Plate  No.  3  and  Plate  No.  4  for  comparison.)  It  may  be 
noted  that  with  the  pyrometer  newly  installed  and  before  the 
gas  maker  knew  its  purpose  the  variation  in  temperatures 
while  the  machine  was  in  operation  was  not  excessive,  being 

Plate  2.     Four  Pyrometer  Recorders  in  Office  of  Gas  Works. 

(The    instruments    are    located    on    the    wall    heside   the    superintendent's   desk 
fully   600  feet   away   from   the   gas   machines   in   the   generator   house.) 

less  than  100  degrees  for  the  24  hours,  excepting  for  the  period 
just  after  cleaning  when  the  temperature  had  to  be  carried 
low  in  the  carbureter  (by  blasting  more  on  the  fire  and  using 
less  secondary  blast)  until  the  superheater  was  cooled  down  to 
a  cherry  red  color  desired.  We  observe  by  means  of  the  super- 
heater indicator  that  the  temperature  of  the  upper  courses  al- 
ways increase  to  1600  or  1800  degrees  during  the  cleaning  or 
clinkering  time,  an  increase  of  as  high  as  400  degrees  above 
operating  temperatures.  This  was  also  noted  in  the  carbur- 
eter (as  shown  by  records,  Plate  No.  5)  although  not  always 
to  such  a  marked  degree  as  shown  in  the  superheater.  When 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER  :      HEATH  167 

you  are  informed  that  it  requires  from  6  to  10  hours  to 
bring  this  excessive  temperature  down*  to  the  desired  1350 
degrees  in  the  superheater  (although  the  carbureter  temper- 
ature can  be  reduced  in  about  an  hour)  you  can  readily  under- 
stand that  this  is  the  period  during  which  coke  is  being  wasted 
and  lamp  black  formed  with  the  resulting  loss  of  candle 
power  in  the  gas  manufactured. 

Improvements  in  the  methods  of  handling  the  machine 
were  then  devised  to  prevent  this  increase  of  temperature  in 
the  brick  work  during  clinkering.  The  gas  machine  had  been 
allowed  to  stand  open  to  the  circulation  of  a  natural  draft  of 
air  through  the  carbureter  and  superheater  and  out  the  stack. 
This  air  would  burn  any  fine  coke  dust  or  lampblack  which 
may  have  lodged  on  the  brick  during  the  previous  period  of 
gas  making  and  thereby  raise  the  temperature  of  the  brick 
far  above  good  operating  conditions.  To  overcome  this  trou- 
ble the  circulation  of  air  through  the  machine  was  stopped, 
on  some  of  the  machines  by  closing  down  the  purge  cap  and 
on  others  by  closing  the  up  and  down  run  valves  in  the  hydro- 
gen pipe  between  the  generator  and  carbureter,  according  to 
local  conditions.  (Note.  Before  starting  to  blast  through  the 
machine  after  clinkering  a  small  amount  of  steam  was  turned 
on  to  cause  a  circulation  through  the  machine  and  prevent 
small  explosions  of  the  gases  which  may  have  formed.)  By 
this  operation  an  even  temperature  was  maintained  in  both 
carbureter,  and  superheater  while  the  stokers  were  removing 
the  clinkers,  but  as  soon  as  the  blast  was  put  on  the  genera- 
tor the  excess  air  for  the  first  few  minutes  while  the  fire  was 
still  cold  would  cause  an  increase  in  temperature  in  the  ma- 
chine for  the  same  reasons.  This  trouble  was  not  so  bad  as 
it  only  took  about  an  hour  or  two  to  bring  the  superheater 
temperatures  down  to  operating  requirements,  but  since  the 
best  operating  conditions  are  none  too  a:ood  from  the  very 
first  minute  that  gas  is  being  made  and  sent  into  the  holders, 
it  was  decided  to  blast  on  the  fires  until  they  were  hot  enough 
to  make  gas  without  allowing  the  excess  air  or  comparatively 
cool  blast  gases  to  pass  through  the  carbureter  and  super- 
heater. To  accomplish  this  the  charging  doors  on  the  top  of 
the  generator  were  opened  and  the  blast  gases  allowed  to  pass 
through  until  considerable  flame  showed  above  the  top  of  the 
coke.     The  primary  blast  valve  was  then  closed,  the  up-run 

*By  means  of  careful  manipulation  of  the  blast  valves,  such  as  increased 
primary  blast  (because  the  temperature  of  the  fire  is  low  after  cleaning) 
and  decreased,  or  often  no  secondary  blast  with  a  large  loss  of  heat  and 
waste  of  coke  from  excess  gases  burning  at  the  stack. 



[May,  1911 

valve  in  the  hydrogen  pipe  or  the  purge  cap  as  the  case  may 
be  was  opened,  the  charging  doors  were  closed,  a  small  amount 
of  steam  turned  on  for  a  moment,  the  primary  blast  valve  fin- 
ally raised,  and  the  entire  machine  was  then  in  the  best  oper- 
ating conditions  before  a  cubic  foot  of  gas  was  sent  into  the 
holders.  With  these  changes  in  the  operation  we  find  that  the 
temperature  in  both  carbureter  and  superheater  is  almost 
constant  during  clinkering  excepting  for  the  slight  loss  due 
to  radiation.     (See  Plate  No.  4— cleaning  time  from  8:05  A. 






i .  M 



•  \« 


ft  l 





M.  to  9:45  A.  M. ;  also,  Plate  No.  14 — cleaning  time  from  10:10 
A.  M.  to  12:00  M. 

By  these  improvements  in  the  methods  of  handling  the  ma- 
chine (which  you  will  notice  can  hardly  be  called  a  change 
in  operation  during  gas  manufacture,  but  rather  was  a  change 
in  the  conditions  of  the  machine  while  idle  and  when  no  one 
would  think  of  watching  the  temperatures  of  checker  brick) 
the  life  of  the  brick  has  been  increased  about  100  per  cent 
and  in  some  cases  as  high  as  175  per  cent  ;and  the  brick  are  now 
quite  free  from  lamp  black  when  the  machine  is  let  down  for 

Vol.  III.  No.  2]     UTILITY   OF   PYROMETER  :      HEATH 


repairs  and  recheckering.  There  is  no  time  lost  for  gas 
making,  as  there  is  no  necessity  of  burning:  out  any  lamp  black 
in  the  machine.  Plate  No.  6  shows  the  clear  cut  outlines  of 
the  brick  as  removed  from  an  11-foot  water  gas  machine.  In 
the  foreground  ;i  portion  of  the  brick  from  the  superheater 
is  shown.  The  condition  of  the  brick  is  better  illustrated  in 
Plate  No.  7.  The  bricks  are  arranged  in  the  direction  of  the 
travel  of  gas  through  the  machine,  starting  at  the  left  side  of 
the  Plate.    The  first  was  taken  from  the  top  course  of  brick  in 

the  carbureter,  the  second  from  the  middle  course,  the  third 
from  the  bottom  course,  the  fourth  from  the  bottom  course  in 
the  superheater,  the  fifth  from  the  middle  course,  and  the  sixth 
from  the  top  course.  The  fifth  and  sixth  bricks  have  been  in  the 
gas  machine  twice,  as  the  upper  half  of  the  superheater  is  al- 
ways checkered  with  old  brick.  The  first  brick  shows  that  some 
of  lighter  fractions  of  the  gas  oil  have  been  burned  on  the  brick, 
which  fact  is  noticeable  only  on  the  first  and  sometimes  second 
course.  This  trouble  is  overcome  in  a  large  measure  by  delay- 
ing the  admission  of  oil  for  a  fraction  of  a  minute  after  the 



[May,  1911 

steam  has  been  turned  on,  thereby  reducing  the  temperature  of 
the  upper  courses  so  that  the  cold  oil  will  not  be  over-cracked, 
or  in  work's  parlance,  taking  the  "sharp  heat"  off  the  top 
courses.  When  the  machine  is  shut  down  for  repairs  the  brick 
immediately  begin  to  cool  and  may  easily  be  removed  by  a 
long  handled  hook  or  by  hand  when  sufficiently  cold,  whereas 
it  previously  required  two  or  three  days  to  burn  out  the  carbon 
and  three  or  four  more  to  cool  off  the  bricks  which  had  be- 
come almost  white  hot  by  the  intense  combustion  of  this  fine 

With  the  carbureter  and  superheater  checkerwork  as  free 
and  open  the  day  the  gas  machine  was  let  down  for  repairs  as 
it  was  the  day  it  was  started,  it  became  necessary  to  determ- 
ine in  a  general  way  by  means  of  the  pyrometer  when  the  life 
of  the  brick  was  exhausted.  When  the  brick  are  new  there 
is  only  a  slight  drop  in  temperature  in  the  bottom  of  the  car- 
bureter with  the  addition  of  a  given  quantity  of  oil  but  as 
the  brick  becomes  old  the  drop  in  temperature  is  greater  for 
the  same  amount  of  oil  used.  The  following  table  shows  the 
loss  in  temperature  as  indicated  by  the  pyrometer  with  its 
fire-ends  placed  in  the  middle  of  the  carbureter  or  nine  courses 
down  from  the  top. 

krol.  Ill,  No.  2]     UTILITY 




SIo.  Machine 

Date  when 

Drop  in  temperature 


new  brick 

old  brick 

No.     7  Machine 

June  1909 



No.     7  Machine 

Oct.  1909 



No.     8  Machine 

Oct.  1909 



No.     9  Machine 

June  1909 



No.     9  Machine 

Oct.  1909 



No.  10  Machine 

July  1909 



No.  10  Machine 

Nov.  1909 



Plate    fi.      Checker   Briek   from    11-foot    Machine 

<ing    Pyrometers. 

This  increased  drop  in  temperature  is  due  in  a  large  meas- 
ure to  the  fact  that  the  heat  stored  in  the  brick  is  not  as 
quickly  conducted  to  the  surface  of  the  old  brick  as  it  is  in  the 
new.  and  therefore  more  heat  is  required  from  the  courses 
farther  through  the  machine  to  fix  the  oil  vapors  as  gases 
when  the  brick  are  old.     It  will  be  noted  in  comparing  the 

115  s 

5   f>   m   w 

*   §  21  £  f 
8      55  8 

H    3  *  2  ™ 
st    °  +*  5  5 

E"1   o   s   si 

S  "  &  L 

.  vrfi 

3  e 

tJ    <u 


a   ?   ca 


O  .a    IS    S 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:     HEATH 

following  table  with  the  preceding  that  although  the  drop  in 
temperature  of  the  brick  is  somewhat  less  in  the  bottom  of  the 
carbureter  or  17  courses  from  the  oil  spray  than  it  is  nine 
courses  from  the  oil  spray  when  the  brick  are  old,  yet  the 
drop  is  very  slight  in  the  bottom  course  when  the  brick  are 

o.  Machine 

Date  when 

Drop  in  temperature 


new  brick    old  brick 

No.  7  Machine 

Oct.  1909 

100               250 

No.  8  Machine 

Apr.  1909 

75              275 

No.  8  Machine 

Oct.  1909 

75              300 

No.  9  Machine 

June  1909 

100              200 

No.  9  Machine 

Jan.  1910 

75              150 

This  increase  drop  in  temperature  upon  the  addition  of 
the  same  quantity  of  oil  per  run  is  a  fair  indication  that  the 
machine  needs  new  checker  brick;  as  the  gas  work's  foreman 
would  say,  the  machine  "won't  hold  her  heats." 

In  order  to  obtain  information  regarding  the  distribution 
of  heat  through  various  types  of  gas  machines  and  the  varia- 
tion in  temperature  at  different  points  in  the  machine  under 
operating  conditions,  I  took  simultaneous  records  of  the  tem- 
peratures at  given  points  for  14  consecutive  days,  noting  the 
changes  in  operation.  The  diagram  of  the  three  types  of  car- 
bureted water  gas  machines  give  a  clear  conception  of  the 
points  at  which  these  continuous  records  were  taken.  (See 
diagram  of  type  1,  2,  3.)  The  black  areas  with  their  corres- 
ponding numbers  indicate  the  position  of  the  fire-ends  in  each 
type,  numbering  from  No.  1  on,  in  the  direction  of  travel  of 
gas  through  the  machine. 

In  type  of  gas  machine  No.  1,  records  were  taken  of  the 
temperatures  of  down-run  gases  at  the  base  of  the  hydrogen 
pipe;  of  up  and  down-run  gases  and  blast  gases  in  the  hy- 
drogen pipe  just  above  the  "Williamson"  water-sealed  hot 
valve ;  of  the  gases  at  the  top  of  the  hydrogen  pipe ;  of  the  first 
course  of  brick  in  the  carbureter;  of  the  12th  course  of 
brick  in  the  carbureter  near  the  center  wall  between  the  car- 
bureter and  the  superheater;  of  the  20th  course  of  brick  at 
wall;  of  the  23d  course  as  shown  in  the  diagram;  of  the  23d 
the  farthest  point  from,  and  at  right  angles  to,  the  center 
course  near  the  center  wall ;  of  the  39th  course  of  brick  (39th 
from  the  oil  spray  or  8th  from  the  bottom  of  the  superheater)  ; 
of  the.  50th  course  of  brick;  of  the  61st  course  near  the 
center  wall;  of  the  61st  course  away  from  the  center  wall;  of 



[May,  1911 

the  62nd  course  at  right  angles  to  the  center  wall   (top  of 

In  type  of  gas  machine  No.  2  records  were  taken  of  the 
temperatures  of  down-run  gases  in  the  generator  4  inches 
below  the  grate  bars ;  in  the  ash  pit ;  and  in  the  hydrogen 
pipe  as  indicated  in  the  diagram;  of  the  temperature  of  up 

run,  down  run  and  blast  gases  at  the  top  of  the  hydrogen 
pipe  near  the  "Levy"  valve;  of  the  9th  course  of  brick  from 
the  oil  spray  in  the  carbureter ;  of  the  13th  course  of  the  17th 
course;  of  the  gases  passing  through  the  connection  pipe  be- 
tween the  carbureter  and  superheater;  of  the  19th  course  (or 
first  course  in  superheater:)  of  the  56th  course  (or  top  of 
superheater;)  and  of  the  gas  in  the  take-off  pipe. 

In  type  of  gas  machine  No.  3  readings  were  taken  from 

Vol.  Ill, No. 2]     UTILITY  OF  PYROMETER:     HEATH  175 

the  top  course  and  bottom  course  of  brick  in  one  shell  and 
the  bottom  and  top  course  of  the  twinshell. 

The  average  temperatures  obtained  by  series  of  tests  on 
type  No.  1  water  gas  machine  may  be  found  in  the  following 
table.  The  first  column  in  the  table  indicates  the  point  at 
which  the  temperature  was  taken  (See  diagram  type  No.  1;) 
the  second  column  indicates  the  number  of  courses  of  checker 
brick  between  each  position  of  the  fire-end  and  the  oil  spray; 
the  third  column  indicates  the  maximum  temperature  at  each 
point,  i.  e..  the  temperature  attained  afer  blasting ;  the  fourth 
indicates  the  minimum  temperature,  i.  e.,  at  the  end  of  the  run; 
the  fifth  indicates  the  loss  in  temperature  at  each  point  upon 
making  gas;  and  the  sixth  indicates  the  average  temperature 
carried  at  each  point. 

Table  No.  1. 





Paint  Brick 



Drop  Average 




(  720 



(  920 





650  1270 





50  1325 





100  1220 





60  1270 





35  1320 





30  1280 





10  1305 





0  1320 





20  1300 





30  1315 


Center  of  12  in.  pipe 

End  of  blasting 

End  of  up  run 

End  of  down  run 

End  of  blasting 

End  of  up  run 

End  of  down  run 

12  in.  from  wall 

12  in.  from  wall 

12   in.    from   wall 
12  in.  from  wall 

In  this  type  of  gas  machine  carbureter  and  superheater 
are  built  side  by  side  within  a  single  shell,  separated  by  a  14- 
inch  center  wall  of  brick  extending  from  the  lower  arch  up  to 
the  top  of  the  machine.  There  are  about  31  courses  of  brick  m 
the  carbureter  and  34  in  the  superheater.  It  will  be  noted 
from  the  above  table  that  the  temperatures  are  quite  uniform 



[May,  1911 

on  both  sides  of  this  wall,  as  shown  by  tests  taken  at  points 
5,  8,  10  and  11,  and  also  that  the  drop  in  temperature  during 
the  run  is  very  small  at  all  these  points.  Evidently  this  wall 
acts  as  a  reservoir  of  heat  tending  to  maintain  more  uniform 
temperatures  throughout  the  fixing  chambers. 

The  first  few  courses  of  brick  performed  the  "heavy  duty" 
of  vaporizing  and  cracking  the  oils  as  is  strikingly  indicated  by 
the  plotted  curve  (see  Plate  11.)  The  cooling  effect  of  the  oil 
on  the  first  course  is  very  marked,  being  about  650  deg  .F., 
while  the  drop  in  temperature  at  the  23rd  course   (point  7) 

in  the  same  relative  position  as  that  taken  at  the  first  course 
(point  4)  is  only  60  deg.  P. 

The  temperatures  of  the  down  run  gases  taken  at  the  base 
of  the  hydrogen  pipe  (point  1)  averaged  625  deg.  F.,  due  to  the 
cooling  action  of  the  grate  bars,  blast  boxes,  etc.,  as  shall  be 
discussed  more  fully  with  type  No.  2.  These  down  run  gases 
are  heated  to  about  700  deg.  F.  at  a  point  3  feet  above  the 
"Williamson"  hot  valve  (point  2)  and  to  920  deg.  F.  at  the  top 
of  this  hydrogen  pipe  (point  3)  the  temperature  of  these  gases 
is  increased  by  the  heat  stored  in  the  fire-brick  lining  of  the 
pipe  during  the  blasting  period.  The  temperature  of  the  blast 
gases  depends  very  largely  on  the  condition  of  the  fire,  as  we 
have  known  in  a  general  way.  When  a  fresh  charge  of  coke  is 
put  into  the  generator  the  temperature  of  the  blast  gases  will 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:      HEATH 

seldom  exceed  1000  deg.  F.,  but  as  each  successive  blasting  in- 
creases the  temperature  of  this  upper  layer  of  coke,  the  gases 
become  hotter  until  they  may  reach  1750  to  1800  deg.  F.,  as 
was  found  after  3  successive  up  runs.  The  down  run  cools  off 
the  top  of  the  fuel  bed  to  such  an  extent  that  the  temperature 
of  the  blast  gases  averaged  100  deg.  F.  lower  than  after  the  pre- 

ceding up  run,  all  other  conditions  being  equal.  It  was  found  that 
the  average  temperature  of  the  blast  gases  at  the  end  of  the 
ulasting  period  was  about  1610  deg.  F.  at  point  No.  2  and  about 
1500  deg.  F.  at  point  No.  3,  showing  a  loss  of  110  degrees  due 
to  radiation  from  the  hydrogen  pipe.  The  temperature  of  the 
up  run  gases  at  the  end  of  the  run  averaged  1360  deg.  at  point 
No.  2  and  1220  deg.  at  point  No.  3,  a  loss  of  140  deg.  due  to 



[May,  1911 

A  test  was  made  to  determine  the  effect  of  radiation  from 
the  shell  of  the  machine  upon  the  temperature  of  the  gases  in 
the  checkered  chamber,  and  thereby  decide  what  should  be  the 
minimum  length  of  the  fire-end.  The  results  are  shown  in  the 
following  table : 


Thickness         At       12  in. from  15  in. from  28  in. from  54in.from 
of  shell  shell  shell  shell  shell  shell 

18  in. 

18  in.  1230°  1280°  1290°  1300°  1300° 

In  a  gas  machine  with  an  18-inch  shell  the  fire-end  should 
be  at  least  4  feet  long. 

The  average  temperatures  obtained  by  series  of  tests  on 
type  No.  2  water  gas  machine  may  be  found  in  the  following 
table : 

Table  No.  2 


Test       of 

Point  Brick  Max. 







4  in.  below  grate  bars 



In  ash  pit 



In  hydrogen  pipe 





Up  run  gases 

5         9 





Old  brick 





New  brick 

6       13 





New  brick 

7       17 





Old  brick 





New  brick 

8  connec 





Gas  Temp. 

tion  pipe 

9       19 





With  Superb.,  blast 





Without  Superb,  blast 

10       56 





With  Superb.,  blast 





Without  Superh.  blast 



In  take-off  pipe 

In   this 

;  type 

of   gas   machine   the 

carbureter   and   super- 

heater  are  in  two  separate  shells  connected  at  the  bottom  by  a 
24-inch  pipe  lined  with  fire  brick.  (See  Type  No.  2.)  The 
curve  plotted  from  the  above  table  (Plate  No.  12)  shows  very 
clearly  that  the  top  nine  courses  of  brick  perform  the  "heavy 
duty"  in  cracking  the  oils;  that  the  average  temperature  of 
the  brick  is  lower  the  farther  the  course  is  from  the  point  at 
which  the  oil  enters;  that  the  variation  in  temperature  during 
each  run  becomes  less  as  the  distance  froni  the  source  of  oil 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:      HEATH 


increases;  that  the  variation  at  the  bottom  of  the  superheater 
is  about  the  same  as  at  the  bottom  of -the  carbureter  excepting 
at  such  times  as  the  gas  maker  uses  the  superheater  blast  for 
one  or  more  runs  when  the  variation  is  about  250  degrees.  1*. 
The  loss  in  temperature  in  passing  through  the  false  bottoms  of 
the  carbureter  and  superheater  and  the  24-in.  connecting  pipe 

Plate   11.      Plot  of  Temperatures   for  Type   jSo.   1   Gas   Machines. 

is  clearly  shown  on  the  curve.  The  temperature  at  the  top  of 
the  superheater  (point  No.  10)  recorded  almost  a  perfect  circle. 
In  the  take-off  pipe  with  the  fire-end  in  the  cross  above  the 
wash-box  (point  11)  Ave  find  that  during  the  run  the  tempera- 
ture of  the  gas  averages  1225  deg.  when  the  temperature  at 
point  10  is  1275  deg.  F. 

It  is  well  at  this  point  of  the  discussion  of  the  temperatures 

1.*  Note. — When  the  superheater  blast  valve  is  opened  wide  the  velocity 
of  the  air  evidently  drives  the  zone  of  combustion  higher  than  No.  0  hole  as 
•toe  tembgatatgw  remains  about  constant  for  the  first  part  of  the  blast  while 
the  temperature  at  No.  10  hole  rises  about  50  degrees.  Toward  the  end 
of  the  blast  when  the  carbon  monoxide  in  the  blast  gases  increases,  the  zone  of 
combustion  is  brought  lower  and  the  temperature  at  No.  !>  increases  about 
the  usual  amount  (100  deg.)  If  the  superheater  blast  is  opened  a  small 
amount  at  first  and  increased  as  much  as  may  be  necessary  during  the  latter 
portion  of  the  blasting,  the  temperature  of  the  brick  at  point  No.  0  increases 
about  250  degrees,  while  at  No.  10  it  increases  only  25  deg.,  indicating  that 
the  zone  of  combustion  is  lower  in  the  superheater. 



[May,  1911 

of  the  brick  in  the  two  types  of  water  gas  machines  to  com- 
pare the  character  of  the  two  curves.  (Plate  No.  11  and  Plate 
No.  12.)  We  find  that  in  type  No.  1  machine  the  oil  has  been 
completely  "cracked"  before  it  leaves  the  carbureter  and  the 
superheater  performs  its  true  function  of  fixing  the  gaseous 
hydrocarbons.  In  type  No.  2  machine  the  curves  indicate  very 
clearly  that  the  oil  has  not  been  fully  "cracked"  in  the  car- 
bureter ;  that  a  large  portion  of  the  work  must  be  completed 
in  the  superheater,  in  addition  to  the  "fixing"  function  of  that 
chamber;  and  that  these  partially  decomposed  hydrocarbons 



[jiiiiiil     :.  :\\\\\iiu\\\\iii:\:M^iM^\ 


Plate   12.      Plot   of   Temperatures   for   Type   No.   2   Gas  Machines. 

are  subjected  to  a  sudden  cooling  of  about  100  degrees  F.  in 
passing  through  the  21-inch  pipe  connecting  the  carbureter 
and  superheater  (which  condition  is  not  found  in  type  No.  1.) 
We  must  therefore  conclude  that  type  No.  1  is  a  much  better 
proportioned  machine  than  type  No.  2. 

A  short  description  of  the  test  on  the  temperatures  of  the 
down  run  gases  before  entering  the  carbureter  may  be  of  in- 
terest. The  fire-ends  were  especially  prepared  to  secure  the 
temperatures  of  the  gases  quickly  and  accurately.  A  half  inch 
iron  pipe  four  inches  shorter  than  the  fire-end  was  used  as  a 
jacket  to  protect  and  support  the  long  wires.  The  hot  junction 
extended  four  inches    beyond  the  open  end  of  this  half  inch 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:     HEATH  181 

pipe  so  as  to  come  in  direct  contact  with  the  down  run  gases, 
while  the  cold  end  was  held  in  a  stuffing  box  packed  with 
asbestos  at  the  outer  end  of  the  half  inch  pipe.  Three  fire-ends, 
prepared  in  this  manner,  were  placed  in  the  bottom  of  the 
generator  about  4  inches  below  the  grate  bars  (point  No.  1)  ;  in 
the  ash  pit  under  the  blast  boxes  (point  No.  2)  ;  and  in  the 
hydrogen  pipe  between  the  generator  and  the  carbureter 
(point  No.  3)  ;  the  results  of  this  test  (sec  Table  No.  2)  indi- 
cate much  lower  temperatures  of  the  down  run  gases  than  was 
anticipated.  The  clinker  and  grate  bars,  cooled  by  the  cold  air 
blast  and  by  the  up  run  steam,  decreased  the  temperature  of 
the  down  run  gases  to  an  average  of  1025  deg.,  the  cold  blast 
boxes  reduced  the  temperature  of  625  deg.  (a  loss  of  400  deg.)  ; 
and  the  radiation  from  the  lower  part  of  the  hydrogen  pipe 
reduced  the  temperature  to  475  deer,  (a  further  loss  of  150  deer.) 

The  relative  temperatures  found  throughout  the  type  No. 
2  gas  machine  are  illustrated  by  the  Composite  Chart  (Plate 
No.  13.)  The  chart  is  composed  of  records  taken  from  eierht 
parts  of  the  machine  during  the  time  between  11 :30  A.  M.  and 
2:30  P.  M.,  and  arranged  in  the  order  of  the  gas  travel.  The 
numbers  indicate  the  position  of  the  fire-end  in  the  gas  machine 
from  which  the  records  were  taken,  as  shown  in  the  diagram 
of  type  No.  2. 

The  third  diagram  shown  (Plate  No.  10)  is  upon  a  type  of 
water  gas  machine  which  is  seldom  seen  in  use  at  the  present 
day,  but  it  illustrates  very  markedly  the  use  to  which  the 
pyrometer  could  have  been  put  as  a  decided  aid  in  operations 
in  the  past.  This  machine  has  two  generators  side  by  side 
connected  by  pipes  and  valves,  above  each  of  which  is  a  fixing 
chamber  filled  with  checker  brick  at  which  point  oil  is  admitted 
for  carbureting  the  gas.  Above  this  short  chamber  is  another, 
but  taller,  fixing  chamber  likewise  filled  with  checkered  brick, 
much  for  the  same  purpose  as  the  superheater  in  the  other 
types.  Each  shell  has  its  own  take-off  pipe,  purge  cap,  wash 
box,  etc.  When  up  runs  are  made  the  steam  enters  the  bottom 
of  each  generator  and  the  two  shells  are  operated  as  independ- 
ent machines.  "When  down  runs  are  made  the  two  shells  are 
operated  together  as  a  single  machine ;  steam  enters  the  top 
of  the  superheater  of  one  shell,  becomes  superheated  steam  in 
passing  through  the  checker  brick,  is  gasified  in  passing  down 
through  one  generator  and  up  through  the  other;  a  large 
quanity  of  oil  is  admitted  in  the  second  fixing  chamber  and  the 
gases  become  properly  fixed  in  the  upper  portion  of  the  twin 
shell.  It  will  be  seen  that  after  a  down  run  the  top  courses 
of  one  shell  will  always  be  considerably  colder  than  the  other. 

182  THE  ARMOUR  ENGINEER  [May,  1911 

To  operate  two  successive  down  runs,  one  on  one  shell  and  the 
second  on  the  twin  shell,  does  not  overcome  this  difficulty,  as 
there  is  always  one  shell  which  will  have  the  last  down  run 
and  that  shell  will  be  colder  than  the  other.  Here  the  pyro- 
meter is  a  great  aid  if  four  fire-ends  are  installed  as  shown  (see 
Plate  No.  10.)  The  primary  and  secondary  blast  on  each  ma- 
chine can  then  be  so  manipulated  with  the  aid  of  the  four  in- 
dicators that  the  colder  shell  may  be  brought  to  the  desired 
temperature  without  heating  the  other  shell  to  an  excessive 
temperature  during  the  blasting  period.  In  this  type  of  ma- 
chine the  top  of  the  superheater  may  be  quickly  cooled  to  the 
desired  temperature  by  reason  of  the  direct  effect  of  the  down 
run  steam. 

It  may  be  of  interest  to  you  at  this  time  to  note  a  few 
features  of  more  or  less  importance  in  the  practical  operation 
of  a  gas  machine  which  I  have  observed  incident  to  the  use  of 
the  pyrometer. 

The  decided  advantage  a  gas  maker  has  in  starting  a  new 
machine  with  the  constant  and  accessible  aid  of  the  pyrometer 
by  heating  the  bricks  uniformly  and  gradually  throughout  the 
machine  without  attaining  an  excessive  temperature  in  the 
carbureter,  is  clearly  shown  by  the  fourth  chart  reproduced 
with  this  article.  (See  Plate  No.  1*4.)  The  record  of  temper- 
atures at  the  bottom  of  the  carbureter  indicates  that  the  blast 
was  turned  through  the  cold  checkerwork  at  1  p.  m.,  August  25. 
1910,  and  that  the  brick  were  slowly  and  steadily  heated  to  a 
temperature  of  1350  deg.  at  this  point  covering  a  period  of  two 
hours.  At  3  :40  P.  M.  the  machine  was  shut  down  for  10  min- 
utes to  readjust  the  oil  meter.  From  10  :10  A.  M.  on  the  fol- 
lowing day  to  12  :00  M.  the  machine  was  cleaned  and  clinkered. 
Note  the  absence  of  any  excessive  temperatures  during  the 
cleaning  time,  but  rather  the  slight  decrease  due  to  radiation. 

When  gas  is  made  with  coke  (blasting  4  minutes  and  run- 
ning 6  minutes)  it  is  very  difficult  to  detect  from  the  chart, 
recording  the  temperatures  in  the  17th  course  from  the  oil 
spray,  just  how  long  the  primary  blast  was  used  before  the 
secondary  was  opened  ;  but,  when  hard  coal  is  used  (blasting 
6  minutes  and  running  6  minutes)  the  chart  shows  very  dis- 
tinctly the  point  at  which  the  secondary  was  opened. 

A  steam  run  is  readily  detected  on  the  chart  thus  enabling 
the  superintendent  to  note  the  carelessness  of  a  gas  maker, 
who  may  allow  the  meter  to  pass  an  excess  of  oil  for  carburet- 
ing during  a  couple  of  runs  and  then  make  the  next  a  steam 
run  to  bring  the  meter  statement  on  the  time  sheet  to  the 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:      HEATH 


reading  of  the  meter  itself.  When  the  gas  makers  realize  that  it 
is  possible  to  cheek  their  work  they  do  become  more  careful. 
There  is  a  certain  moral  influence  surrounding  the  pyrometer, 
a  halo  of  mystery  enveloping  that  chart  over  in  the  office, 
which  the  average  gas  maker  greatly  respects.  He  will  even 
refrain  from  smoking  in  its  presence  for  some  months. 

Plate    13.      Composite    Pyrometer    Records    of    Comparative    Temperatures    on 
Type  No.  2  Water  Gas  Machines. 

(This  chart  indicates  the  temperatures  in  eight  different  points  on  the  gas 
machine  from  11:30  a.  in.  to  2:30  p.  in.  The  numbers  designating  each 
segment  indicate  the  relative  position  of  the  tire-ends  in  the  machine  and 
correspond  to  the  numbers  on  Plate  No.  !•. 

Another  feature  which  is  readily  d 
bureter  instrument  is  the  action  of  the  oi 
properly  adjusted,  some  of  the  openings 
carbon,  or  the  spiral  fails  to  rotate  (as  in 
the  oil  will  cool  the  brick  in  one  portion 
causing  the  familiar  "dark  streaks"  in 
this  connection  T  might  say  that  the  eh< 
of  different   types  of  sprays  has   been  s 

etected   by   the   car- 

1  spray.     If  it  is  not 

become  closed  with 

the  Johnson  spray), 

more  than  another, 

the    carbureter.     In 

lice  between  the  use 

implified   in   a   large 

184  THE   ARMOUR  ENGINEER  [May,  1911 

measure.  On  the  one  hand  a  stationary  spray  was  recom- 
mended which  had  no  movable  parts  and  required  a  minimum 
of  repairs  but  gave  a  slight  "dark  streak"  in  the  center  of  the 
carbureter,  a  condition  which  could  not  be  avoided;  while  on 
the  other  hand  a  spray  was  recommended  which  had  to  be 
raised  above  the  carbureter  arch  after  every  run  to  keep  it 
from  the  heat  of  the  blast  gases  and  which  had  movable  parts, 
necessitating  occasional  repairs,  but  gave  no  dark  streaks 
when  adjusted.  The  many  advantages  of  the  former  spray 
were  not  of  sufficient  weight  for  its  adoption  when  the  pyro- 
meter indicated  that  this  "dark  streak"  represented  a  tem- 
perature about  1000  deg.  F.,  whereas  the  temperature  of  the 
brick  2  feet  from  the  center  was  1350  deg.  F. 

The  instruments  in  the  carbureter  and  superheater  aid 
the  gas  maker  in  determining  the  condition  of  his  generator. 
If  the  stack  gases  show  excessive  flame  at  the  purge  cap  (due 
to  the  combustion  of  an  excessive  supply  of  carbon  monoxide 
formed  in  the  generator)  when  the  temperatures  in  the  car- 
bureter and  superheater  are  at  the  desired  points,  the  fire  is 
too  hot  and  the  primary  blast  valve  should  not  be  opened  so 
wide  during  the  following  blow.  When  the  fire  is  not  -hot 
enough  to  generate  sufficient  carbon  monoxide  to  heat  the 
checker  work  to  the  desired  temperature  and  to  show  a  thread 
of  blue  flame  at  the  stack  toward  the  end  of  the  blow,  more 
primary  blast  should  be  given  to  the  generator.  By  operating 
in  such  a  manner  the  pyrometer  will  aid  materially  in  main- 
taining a  good  fire,  and  reduce  the  amount  of  coke  wasted  by 
excessive  blasting  with  the  primary. 

I  recall  one  very  interesting  incident  which  occurred 
about  a  year  ago.  The  recording  chart  taken  from  the  instru- 
ment on  the  morning  of  a  sweltering  July  day  indicated  a  drop 
in  temperature  every  run  or  two  during  the  previous  after- 
noon and  night.  After  the  oil  spray  had  been  examined  and 
found  to  be  in  excellent  condition,  the  chart  was  again  referred 
to  and  studied  more  closely.  It  was  noted  that  there  was  a 
certain  regularity  to  the  repetition  of  this  increased  variation 
in  temperature  (about  twice  the  average  variation)  ;  that  it 
occurred  every  second  and  third  run  in  the  same  order  in 
which  the  down  runs  occurred.  Upon  examination  of  the  hot 
valve  between  the  top  of  the  generator  and  the  hydrogen  pipe, 
a  small  quantity  of  coke  breeze  was  found  in  the  seat  of  the 
valve  which  prevented  a  tight  seating  of  the  gate  during  a 
down  run  and  permitted  live  steam  to  escape  from  the  top 
of  the  generator  to  the  carbureter,  causing  the  increase  in  the 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER  :     HEATH 


cooling  of  the  brick  during  the  run.    It  is  needless  to  say  that 
the  trouble  was  immediately  remedied. 

Before  giving  a  short  summary  of  the  results  obtained 
with  the  pyrometer  in  carbureted  water  gas  machines  it  will 
be  hardly  necessary  for  me  to  emphasize  a  few  points  which  I 
consider  of  chief  importance.  Lamp  black,  I  believe,  is  formed 
to  a  large  extent  when  the  machine  is  started  up  after  recheck- 
ering  with  new  brick.  The  heat  in  the  top  of  the  carbureter  is 
allowed  to  run  too  high  so  as  to  obtain  the  desired  cherry  red 

heat  in  the  superheater  as  soon  as  possible.  Lamp  black  is  also 
formed  by  excessive  temperature  on  the  checkerwork  after 
the  machine  has  been  idle  during  the  clinkering  time  caused  by 
the  natural  draft  through  the  carbureter  and  superheater. 
Methods  employed  to  overcome  these  difficulties  have  been  pre- 
viously discussed. 

The  theoretic  operation  of  a  water  gas  set  would  be  the 
manufacture  of  gas  with  as  high  a  temperature  as  possible  in 
the  checker  brick  without  the  formation  of  lamp  black  and 
thereby  obtain  the  greatest  possible  proportion  of  fixed, 
gaseous  hydrocarbons.    Tn  practice  we  find  other  factors  enter- 



[May,  1911 

ing  the  problem  which  limit  the  temperatures  to  be  carried  in 
the  superheater,  and  it  will  be  noted  how  narrow  these  limits 
are.  Temperatures  above  1500  deg.  F.  produce  considerable 
lamp  black  in  the  superheater.  A  machine  which  carries  1450 
deg.  F.  in  the  superheater  would  produce  some  lamp  black  and 
would  fill  the  works  with  naphthalene  in  a  short  period  of 
time.  One  carrying  1400  deg.  F.  produces  some  naphthalene 
trouble  but  practically  no  lamp  black.  Machines  operating 
from  1300  deg.  to  1340  deg.  F.  produce  hardly  a  trace  of 
naphthalene  in  the  entire  plant.  Under  1250  deg.  F.  the  ma- 
chines have  dirty  seal  pots  showing  tar  and  uncracked  oils.  The 
practical  limitations  in  gas  machine  control  are  then  complete 
decomposition  of  the  heavier  hydrocarbon  oils  and  no  serious 
trouble  from  the  formation  of  naphthalene,  i.  e.,  clean  seal  pots 
and  a  minimum  amount  of  naphthalene.  Best  practice  keeps 
the  temperature  of  the  superheater  between  the  rather  narrow 
limits  of  1300  deg.  to  1400  deg.  F.  These  temperatures  are 
based  upon  the  use  of  gas  oil  having  a  gravity  between  33  deg. 
Be  and  35  deg.  Be  of  approximately  the  following  analysis : 


#  BY  WOT. 

SP.  OR. 


From    0°to300°F 




300  to  400 




400  to  500- 




500  to  600 




600  to  700 




700  and  above 

5.86  Resa 

due  Tar. 

Sp.  Gr.  of  r»l=-      . 8630       corresponding  to 53.2* °Baume 

Flash  point—: 1S&1 °F. 

Burning  point 

=         196' 


In  a  general  way  it  may  be  stated  that  with  a  given  quan- 
tity of  oil  used  to  carburet  the  water  gas  a  temperature  of 
approximately  1250  deg.  in  the  fixing  chamber  will  yield  a  gas 
of  about  16%  methane  with  correspondingly  low  heat  value, 
while  temperatures  approximating  1350  deg.  would  yield  a  gas 
with  nearly  20%  of  methane,  and  relatively  high  B.  T.  U.  and 

Vol.  Ill,  No.  2]     UTILITY   OF   PYROMETER:     HEATH  181 

temperatures  approximating  1400  deg.  would  yield  a  gas  con- 
taining as  high  as  22%  methane. 

In  conclusion  I  wish  to  summarize  in  a  brief  way  the  prin- 
cipal results  obtained  by  the  pyrometer,  directly  or  indirectly, 
in  the  practical  operation  of  a  carbureted  water  gas  set. 

The  first  and  probably  most  essential  point  is  that  a  uni- 
form temperature  can  be  maintained  in  the  machine  and  unless 
the  gas  maker  has  had  considerable  experience  this  is  a  con- 
dition difficult  to  obtain  without  an  instrument. 

Second,  the  carbureting  and  fixing  chambers  have  been 
closed  during  the  clinkering  time  in  such  a  manner  as  to  pre- 
vent uneven  and  excessive  temperatures. 

Third,  methods  of  operating  the  blast  valves  have  been  de- 
vised so  as  to  maintain  a  healthy  condition  of  the  generator 
fire,  with  a  minimum  waste  of  carbon  monoxide  gas  burning 
at  the  stack. 

Fourth,  the  absence  of  lamp  black  on  the  checker  work 
when  the  machine  is  shut  down  for  repairs  is  an  indication  that 
the  oil  for  carbureting  has  been  utilized  to  the  best  advantage. 

Fifth,  the  freedom  of  the  works  from  naphthalene  has 
solved  many  problems,  especially  the  disadvantages  of  using 
oxide  saturated  with  the  light,  flaky  crystals  in  purification  of 
the  gas. 

Sixth,  the  gas  maker  can  operate  his  machine  more  care- 
fully and  intelligently  with  the  constant  and  accessible  indica- 
tion of  the  temperatures  in  various  parts  of  the  machine. 

Seventh,  the  continuous  record  of  temperatures  carried  on 
each  machine  by  night  as  well  as  day  shifts  in  the  office  where 
the  superintendent  may  find  ready  reference^  is  of  untold  value. 

Eighth,  the  indicator  and  recorder  will  easily  show  the 
condition  of  the  oil  spray.  The  charts  indicate  very  clearly  the 
time  taken  by  each  machine  in  charging,  clinkering,  repairing 
or  waiting. 

Ninth,  the  pyrometer  may  be  utilized  to  indicate  the  useful 
life  of  the  checker  brick. 

Tenth,  a  better  knowledge  of  the  exact  temperatures 
found  in  various  parts  of  the  machine  becomes  very  useful  in 
practical  operations. 

Eleventh  and  final,  the  extended  use  of  the  pyrometer  in 
operating  all  the  machines  in  the  plant  under  a  given  tempera- 
ture for  a  considerable  period  of  time,  and  subsequently  under 
other  known  temperatures  for  sufficient  time,  has  proven  of 
great  value  in  determining  the  practicable  range  of  tempera- 
ture for  good  operating  conditions  in  the  carbureted  water 
gas  machines. 


By  RAY  S.  HUEY,  E.  E  * 

Portland  cement  is  now  almost  as  familiar  to  the  general 
public  as  wood  or  stone,  and  its  uses  have  become  so  general 
and  diversified  that  it  has  become  an  invaluable  material  for 
durable  and  fireproof  articles  in  the  arts  and  sciences.  The 
fact  that  Portland  cement  is  so  easily  worked,  and  that  almost 
anyone  of  average  intelligence  can  do  a  creditable  job  with  it, 
makes  it  a  building  material  for  which  there  is  an  ever  increas- 
ing demand.  It  also  has  the  advantage  of  being  a  product, 
the  raw  material  for  the  manufacture  of  which  can  be  found 
in  almost  any  locality  in  the  world,  and  if  the  demand  is  great 
enough  can  be  made  close  to  the  locality  in  which  it  is  to  be 
used,  thereby  reducing  the  cost  of  transportation. 

Portland  cement  is  a  combination  of  silica,  iron,  alumina, 
and  lime,  in  proper  proportions,  the  raw  materials  of  which 
may  be  obtained  from  shale,  clay  or  blast  furnace  slag  and 
limestone  or  marl.  The  process  of  manufacture,  using  the 
blast  furnace  slag  and  limestone,  at  the  Buffmgton  plants 
(Nos.  3,  4  and  6)  of  the  Universal  Portland  Cement  Company, 
is  the  one  which  will  here  be  described. 

Many  persons  are  under  the  impression  that  the  slag  from 
furnaces  of  any  description,  blast  or  open-hearth,  can  be  uti- 
lized for  making  cement,  but  this  idea  is  erroneous.  Slag  suit- 
able for  cement  is  very  carefully  made,  and  of  suitable  mate- 
rials— for  example,  the  slag  from  a  blast  furnace  using  dolo- 
mite (magnesium  limestone)  as  a  flux  cannot  be  used  because 
the  percentage  of  magnesia  in  the  cement  would  be  too  great 
to  pass  standard  specifications. 

Slag  is  a  logical  raw  material  for  making  Portland  cement ; 
it  contains  roughly  36%  silica,  14%  iron  and  alumina,  and 
about  46%  lime,  is  readily  fusible,  and  simply  requires  the 
addition  of  more  lime  in  the  proper  proportions  to  make  the 
mixture  for  first-class  Portland  cement.  It  is  in  a  finely  di- 
vided state,  so  does  not  require  crushing,  and  consequently 
is  readily  handled.  Blast  furnace  slag  suitable  for  use  in  the 
manufacture  of  cement  is  made  by  allowing  the  molten  stream 
of  slag  to  run  from  the  furnace  to  a  tank  where,  as  it  falls  off 
the  trough,  it  is  struck  by  a  stream  of  high-pressure  water 
which  cools  and  disintegrates  it  immediately.  It  is  then  loaded 

'Class  of  1899.     Asst.   Superintendent   Plants  3,  4,   and  6,  Universal   Portland 
Cement   Co.,   Bufflngton,   Ind. 

Vol.  Ill,  No.  2]       CEMENT  MANUFACTURE:     HUEY 


into  hopper-bottom  steel  freight  cars  by  a  traveling  crane, 
which  digs  the  granulated  slag  out  of  the  water  by  a  clam- 
shell bucket,  and  shipped  to  the  cement  plant  where  it  is 
dumped  from  a  trestle  into  large  bins.  The  slag  is  in  small 
particles,  slightly  resembling  sand  in  size  and  color,  and  con- 
tains a  large  percentage  of  water,  varying  between  20%  and 
40% — depending  upon  the  physical  character  of  the  particles 
and  the  temperature  at  which  it  was  granulated. 

Granulating  the  Slag  at   the  Blast  Furnace. 

This  slag  is  discharged  from  the  raw  material  bins  into 
elevators  which  carry  it  to  the  dryers,  these  being  slowly  re- 
volving cylinders  having  compartments  lined  with  flights  which 
turn  the  material  over  and  over  and  keep  it  traveling  toward 
the  discharge  end,  allowing  hot  gases  to  come  in  contact  with 
the  wet  slag  and  drive  off  the  moisture. 

The  slag  is  now  elevated  again  in  bucket  elevators  and 
spouted  to  various  ball  mill  feed  hoppers  which  are  intended  to 
keep  a  sufficient  stock  in  them  to  keep  a  mill  supplied  for  some 
time,  should  the  preceding  machine  which  supplies  the  hopper 
have  to  be  shut  down  for  repairs.  The  slag  is  preliminary 
ground  in  a  ball  mill,  conveyed  to  an  elevator  by  a  belt  con- 



[May,  1911 

veyor,  and  again  elevated  to  hoppers  over  the  weighing  ma- 
chines or  scales.  The  ball  mill  consists  of  a  pair  of  steel  discs 
mounted  on  a  shaft  about  5'  apart,  having  20  heavy  cast-steel 
wearing  plates  mounted  near  the  circumference.  Ten  of  these 
plates  are  solid  and  ten  are  perforated,  and  are  mounted  in 
such  a  way  that  when  the  4,500  pounds  of  4"  steel  balls  fall 
on  the  material  to  be  crushed,  some  will  be  crushed  and  go 
through  the  perforated  plate.  Between  the  steel  wearing  plates 
and  the  periphery  of  the  disc  are  two  sets  of  screens,  consisting 

Scales  for  Weighing  the  Raw  Material  Mixture. 

of  one  set  of  heavy  protecting  screens  of  perforated  metal 
which  protects  the  lighter  and  finer  wire-cloth  screen  on  the 
outside  from  injury  in  case  a  steel  plate  breaks,  and  which  also 
takes  the  wear  off  the  lighter  screen  from  material  which  could 
not  possibly  go  through  the  fine  screen.  All  the  material  which 
does  not  go  through  is  returned  to  the  plates  and  crushed  until 
it  will  go  through. 

The  limestone,  which  is  the  other  ingredient  of  the  raw 
material  mixture,  is  quarried  at  the  Company's  quarry  in  the 
Fairmount  District,  crushed  to  about  a  6"  cube  or  smaller, 
shipped  in  steel  hopper  cars  and  unloaded  into  the  trestle  bins 

Vol.  Ill,  No.  2]   CEMENT  MANUFACTURE:  HUEY  191 

in  the  same  manner  as  the  granulated  slag.  It  is  then  crushed 
to  about  l1/^"  in  a  gyratory  crusher,  elevated  to  a  dryer,  dried 
and  ground  in  the  same  manner  as  the  slag. 

The  dried  slag  and  stone  are  in  separate  bins  above  a  pair 
of  tandem,  automatic,  electrically  operated  scales,  and  are 
conveyed  to  the  scale  hoppers  by  means  of  screw  conveyors. 
The  scales  are  arranged  so  that  a  contact  is  made  with  a  dump- 
ing mechanism,  which  discharges  both  scale  hoppers  simultan- 
eously after  both  are  up  to  full  weight.  The  material  is  then 
mixed  and  carried  by  a  screw  conveyor  from  a  hopper  below 
the  scales  to  a  bucket  elevator  which  spouts  the  mixture  to  the 
tube  mill  hoppers. 

The  final  raw  material  grinding  is  done  in  tube  mills,  each 
of  which  is  a  tube  5'  or  6'  in  diameter  and  22'  long,  and  lined 
with  hard  cast-iron  plates  bolted  to  the  shell.  The  shell  is 
supported  by  a  head  at  each  end  on  which  is  a  hollow  trunnion, 
the  material  being  fed  into  the  trunnion  at  one  end  and  dis- 
charged through  the  one  at  the  other  end.  This  mill  is  about 
half-filled  with  flint  pebbles  and  is  revolved  at  about  25  revolu- 
tions per  minute,  thus  causing  the  material  to  be  crushed  to  a 
fine  powder  by  the  falling  of  the  pebbles  on  it,  The  finished 
raw  material  mixture  is  taken  on  a  belt  conveyor  to  an  eleva- 
tor, and  then  across  a  bridge  by  a  screw  conveyor  to  the  hop- 
pers over  the  feed  end  of  the  rotary  kilns  in  the  burner  build- 

The  kilns  are  steel  shells  lined  with  fire-brick  about  7'-6" 
in  diameter  and  120'  long,  and  are  set  on  a  pitch,  which,  when 
the  kiln  is  revolved,  tends  to  move  the  material  toward  the 
lower  end.  The  kilns  turn  around  once  per  minute  and  by  the 
time  the  material  is  discharged  at  the  lower  end  it  has  been 
fused  by  intense  heat  into  balls  called  clinker.  The  rotaries 
and  dryers  are  heated  through  the  combustion  of  pulverized 
coal  blown  in  by  an  air-blast,  this  producing  a  flame  that  ap- 
pears very  much  like  a  big  gas  flame  and  a  temperature  of 
about  2350°  F.  at  the  hottest  end  of  the  kiln. 

The  pulverized  coal  is  produced  by  crushing  and  drying 
coal  screenings  and  then  pulverizing  them  in  fuller  mills,  one 
of  which  consists  of  a  vertical  shaft  having  mounted  on  it  a 
spider  which  pushes  four  9"  balls  around  a  hard  cast  iron  ring 
with  sufficient  velocity  to  furnish  the  necessary  centrifugal 
force  to  crush  the  coal.  By  means  of  a  fan  attached  to  the 
main  shaft  above  the  balls  the  fine  coal  is  blown  through  the 

The  clinker  is  now  elevated  and  spouted  into  a  large  open 
bin  holding  about  75,000  barrels,  and  is  picked  up  and  dis- 



[May,  1911 

tributed  by  traveling  cranes,  to  which  are  attached  large  clam- 
shell buckets.  While  on  the  pile  the  clinker  is  sprinkled  with 
water  until  it  contains  about  l1/2%  moisture,  this  being  to  slack 
out  the  free  lime  which  is  always  present  in  small  amounts  in 
fresh  clinker.  When  properly  seasoned,  it  is  picked  up  again 
by  the  cranes  and  put  into  the  hoppers  over  the  clinker  crush- 
ers in  the  finishing  mill.  In  jaw-crushers,  the  large  lumps 
are  crushed  to  about  1"  in  diameter,  and  the  clinker  falls  into 
the  Maxecon  mills,  to  be  granulated. 

Rotary    Kilns    in   Burner   Building. 

The  Maxecon  mill  is  a  machine  composed  essentially  of  a 
ring  having  a  concave  inner  surface,  and  three  rolls  having 
convex  outer  surfaces  made  of  hard  material.  The  rolls  are 
set  120°  apart  and  pull  out  against  the  inside  of  the  ring.  The 
tension  between  the  ring  and  the  rolls  is  regulated  by  a  spring, 
each  one  of  which  reacts  between  the  frame  of  the  machine  and 
a  yoke  on  which  are  mounted  the  bearings  for  the  shaft  hold- 
ing each  roll.  The  top  roll  is  driven,  and  this  through  friction 
drives  the  ring  which  in  turn  drives  the  two  bottom  rolls.  The 
material  to  be  crushed  is  fed  in  between  the  ring  and  one  roll 
and  the  centrifugal  force  carries  it  around  inside  of  the  ring 
to  the  next  roll,  this  continuing  until  it  drops  off  through  the 
frame  to  the  elevator.     The  elevator  then  lifts  the  crushed  ma- 

Vol.  Ill,  No.  2]       CEMENT   MANUFACTURE:     IIUEY 


terial  to  a  screen  in  which  the  fine  material  is  separated  and 
taken  to  the  gypsum  scale.  The  coarse  material  remaining  is 
returned  to  the  Maxecon  mills  to  be  crushed  again. 

By  means  of  automatic  weighing  machines  about  2%  gyp- 
sum (calcium  sulphate)  is  added  to  regulate  the  setting  time 
of  the  cement.  Cement  without  gypsum  would  set  in  aboul 
3  or  4  minutes,  so  it  can  readily  be  seen  that  it  would  be  use- 
less to  work  with  as  a  building  material,  for  the  most  rapid 

Maxeion   Mill   for   Preliminary    Grinding   of  Clinker. 

mixer  and  workmen  would  be  unable  to  mix  and  place  the  con- 
crete before  it  would  set. 

From  the  gypsum  scales  the  ground  clinker  is  again  ele- 
vated to  the  hoppers  over  the  tube  mills  and  given  a  final 
grinding.  The  cement  in  this  condition  is  finished  and  is  con- 
veyed by  a  belt  conveyer  from  the  tube  mills  to  the  storage 

194  THE  ARMOUR  ENGINEER  [May,  1911 

bins  in  which  it  is  kept  until  required  for  shipments.  When 
this  is  desired  it  is  drawn  out  from  the  bottom  of  storage  bins, 
through  gates  into  the  screw  conveyors  to  elevators,  thence  to 
packing  hopper,  packed  by  automatic  weighing  machines  into 
^-barrel  sacks,  either  in  paper  or  cloth,  and  loaded  into  cars 
for  shipment. 

The  total  combined  capacity  of  all  the  plants  of  the 
Universal  Portland  Cement  Company  is  40,000  barrels  per 
day,  of  which  27,000  are  made  at  Buffington,  in  Plants  3,  4 
and  6.  This  requires  about  200  cars  of  raw  material,  and 
about  100  to  300  cars,  depending  on  the  season  of  the  year, 
are  required  every  day  in  which  to  ship  the  finished  product. 

The  finished  cement  is  sampled  by  an  automatic  sampler 
once  every  eight  seconds,  and  this  sample  taken  to  the  labora- 
tory every  hour  where  complete  tests  for  fineness,  setting  time, 
and  soundness  are  made.  Every  car  is  sampled  before  ship- 
ment, and  the  same  tests  made  in  order  that  there  may  be  com- 
plete records  for  reference.  About  96%  of  the  finished  cement 
will  pass  through  a  100-mesh  sieve,  which  has  10,000  holes  per 
square  inch — the  diameter  of  the  wire  forming  the  sieve  being 
.0045".  About  80%  will  pass  through  a  200-mesh  sieve,  hav- 
ing 40,000  holes  per  square  inch — the  wire  in  this  case  being 
.0024"  in  diameter. 

Chemical  analyses  are  made  continually  to  keep  the  in- 
gredients in  the  raw  material  constant,  and  strength  tests  and 
analyses  are  made  daily  to  see  that  the  duality  is  kept  up  well 
above  the  standard  requirements. 

All  the  machinery  is  electrically  driven,  and  requires  ap- 
proximately 10,000  H.  P.  at  the  sub-station  switchboard.  The 
power  required  is  generated  by  the  waste  gas  from  the  blast 
furnaces,  by  either  steam  engines,  steam  turbines  or  gas  en- 
gines, and  transmitted  ten  miles  at  22,000-volts,  3-phase,  and 
25-cycles,  to  the  sub-station  in  which  it  is  transformed  to  440- 
volts  and  distributed  to  the  different  buildings  by  independent 
switches,  so  that  in  case  of  trouble  in  one  building  it  can  be 
disconnected  and  the  trouble  remedied.  The  machines  are 
individually  driven  and  as  far  as  possible  direct  connected, 
thus  eliminating  many  belts  and  geared  speed-reducing  de- 
vices. This  makes  it  possible  to  shut  down  each  machine  for 
repairs,  when  necessary,  without  disturbing  the  rest  of  the 
mill,  and  so  allows  the  mechanical  department  to  keep  the 
plant  in  a  better  state  of -repairs. 

The  motors  are  all  of  the  squirrel-cage  induction  type  and 
give  very  little  trouble  under  the  severe  loads  and  dust  condi- 
tions which  are  found  in  a  cement  plant.     The  progress  made 

Vol.  Ill,  No.  2]       CEMENT   MANUFACTURE:     HUEY 


in  the  improvement  of  machinery  for  grinding  cement  has  heen 
remarkable  in  the  last  ten  years  and  nearly  all  the  machinery 
installed  then  is  now  out  of  date. 

From  a  college  man's  standpoint  a  cement  plant  is  an  in- 
teresting place.  To  be  a  successful  operating  man  at  the  head 
of  a  large  cement  plant,  he  should  be  a  chemical,  mechanical 
and  electrical  engineer  combined,  and  the  more  thorough  the 
ground-work  the  more  capable  man  he  will  be.     In  detail,  re- 

Device    for    Automatically    Sampling    Cement. 

garding  the  engineering  qualifications  of  the  head  of  such  a 
plant,  he  should  know  the  effect  of  certain  variations  of  the 
raw  material.  It  is  also  necessary  to  know  the  effect  of  the 
chemical  constituents  of  the  steel  and  other  materials  which 
are  used  in  machinery,  in  order  to  get  the  most  efficient  and 
durable  material  to  be  used  in  new  machinery,  or  in  making 
repairs.  As  a  mechanical  engineer  he  is  called  upon  to  figure 
strength  of  parts,  size  of  pulleys,  capacity  of  machinery,  and 
design  new  improvements. 

Since   my    connection    with    the    cement    plant,    my  view- 
point   regarding    machinery    has     been     entirely     revolution- 

196  THE  ARMOUR  ENGINEER  [May.  1911 

ized.  I  formerly  thought  that  when  a  machine  was  pur- 
chased it  was  ready  to  do  the  work  for  which  it  was  de- 
signed without  any  changes.  I  have  found,  however,  that  with 
few  exceptions  there  is  hardly  a  machine  on  the  market  which 
does  not  need  reconstruction  to  make  it  better  and  more  adapt- 
able to  the  work  required  of  it  and  there  is  frequently  a  small 
detail,  the  lack  of  which  will  make  it  a  failure.  It  is  here  that 
a  thorough  knowledge  of  mechanical  engineering  coupled  with 
a  practical  experience  gained  under  individual  conditions  is 
valuable.  It  is  therefore  necessary  to  scrutinize  carefully  the 
detail  drawings  of  every  machine  and  try  to  see  in  one's  mind 
Avhether  the  design  of  a  new  machine  cannot  be  altered  to  adapt 
it  to  the  work  to  be  performed  in  your  particular  plant,  as 
most  machinery  seems  to  be  designed  by  persons  who  have  had 
little  practical  operating  experience,  and  consequently  know 
but  little  of  the  difficulties  which  are  encountered  in  the  opera- 
tion of  their  own  machinery. 

On  account  of  the  increasing  use  of  motors  and  electrical 
apparatus  in  connection  with  the  cement  industry,  if  one  is  to 
be  familiar  with  the  details  of  the  work  under  him  he  must  be 
qualified  to  pass  on  the  design  of  motors  and  transformers  and 
all  kinds  of  improved  electrical  apparatus  which  must  be  built 
to  suit  certain  conditions.  He  must  be  able  to  design  and  cal- 
culate new  installations  and  make  specifications  to  meet  his 
peculiar  requirements.  He  must  also  know  how  to  diagnose 
electrical  troubles  and  prescribe  the  cure.  When  one  is  quali- 
fied to  meet  all  the  above  specifications,  he  still  has  the  most 
difficult  problem  before  him,  which  is  that  of  handling  men. 
To  have  a  good  organization  which  will  pull  together  and  pro- 
duce results  at  a  minimum  cost,  is  the  goal  of  every  man  in  an 
executive  capacity,  not  only  in  the  cement  industry,  but  in 
every  other  kind  of  business. 



(A  Review  Compiled  from  the  Literature.) 

It  may  be  well  at  the  outset  to  define  what  is  meant  by 
"Synthetic  Eubber"  or  "Synthetic  Caoutchouc."  The  India- 
Rubber  Journal,  Vol.  34  (1907),  p.  519,  defines  it  as  a  substance 
"built  up  by  chemical  means,  *  *  *  and  possessing  all  the 
physical  and  chemical  properties  of  natural  rubber."  If  we 
consider,  however,  the  molecule  of  the  natural  rubber  hydrocar- 
bon as  having  an  empirical  formula  C10H16,  it  will  be  necessary 
to  modify  this  definition  somewhat  to  include  other  products 
having  all  the  physical  properties  of  natural  rubber  but  whose 
chemical  properties,  owing  to  variations  in  empirical  or  struc- 
tural formulae,  may  be  either  identical  with,  or  analogous  to, 
those  of  the  natural  caoutchouc.  The  existence  of  the  so-called 
homologous  caoutchoucs,  probably  differing  in  empirical  form- 
ulae from  that  given  above,  will  be  hereinafter  referred  to  more 
at  length. 

Synthetic  rubber,  then,  is  the  product  of  a  chemical  process 
as  distinguished  from  the  natural  product  which  is  obtained 
from  the  latex  of  rubber-producing  plants.  In  composition  and 
properties,  however,  the  synthetic  product  may  be  considered 
the  same  as,  or  equivalent  to,  the  pure  india-rubber  hydrocar- 

The  distinction  between  the  real  synthetic  rubber,  and  the 
so-called  artificial  rubbers  and  rubber  substitutes  should  be 
kept  clearly  in  mind.  These  latter,  which  are  sometimes  im- 
properly called  synthetic  rubbers,  generally  possess  some  of  the 
physical  characteristics  of  natural  rubber,  but  may  not  be  even 
remotely  related  to  it  chemically.  They  may  consist  either  of  a 
greater  or  less  percentage  of  natural  rubber  together  with  va- 
rious fillers  and  diluents,  or  they  may  consist  entirely  of  vulcan- 
ized oils  or  gums. 

It  is  the  purpose  of  the  present  article  to  review,  more  or 
less  completely,  the  literature  which  has  up  to  the  present  time 
appeared  on  the  subject  of  synthetic  rubber,  its  formation  and 

It  has  long  been  known  that  an  intimate  relationship  exists 
between  isoprene  and  caoutchouc,  isoprene  being  one  of  the 
products  of  the  destructive  distillation  of  caoutchouc,  and  being 
itself  capable,  under  suitable  conditions,  of  being  again  con- 
verted into  caoutchouc  by  polymerisation.     Many  experiment- 

*Fornierly    of    Class    of    1910.      Assistant     Examiner,     U.     S.     Patent     Office, 
ington,   D.   C. 

198  THE  ARMOUR  ENGINEER  fMav.  1911 

ers  have  observed  these  phenomena.  It  is  therefore  natural  that 
the  term  "synthetic  rubber"  should  first  suggest  the  product 
made  from  isoprene.  A  discussion  of  this  hydrocarbon,  and  of 
the  caoutchouc  made  from  it,  will,  therefore,  first  be  given. 

Isoprene,  as  is  well  known,  has  the  structural  formula  CHL,  :C 
(CH3).  CH:CH2,  corresponding  to  the  empirical  formula  C5H8. 
It  is  a  member  of  the  di olefin  series  of  hydrocarbons,  containing 
two  double  bonds,  and  is  chemically  beta-methyldivinyl,  or  2. 
methyl-1.3-butadien.  It  was  first  identified  and  studied  by  Wil- 
liams in  1860  (J.  Chem.  Soc,  1862,  Vol.  XV,  p.  110),  who  iso-. 
lated  it  from  among  the  products  of  the  destructive  distillation 
of  caoutchouc.  Mention  of  its  polymerisation  was  also  first 
made  by  Williams  at  this  same  time.  He  observed  that  when 
isoprene  was  left  standing  for  some  months  it  absorbed  oxygen 
from  the  air,  became  viscid,  and  acquired  powerful  bleaching 
properties.  When  this  product  was  carefully  distilled,  un- 
changed isoprene  first  passed  over,  the  temperature  suddenly 
rose  with  evolution  of  ozone,  and  the  contents  of  the  retort  soi- 
idified  to  a  pure  white,  spongy  elastic  mass  having  but  slight 
tendency  to  adhere  to  the  fingers.  When  burnt  it  gave  the  char- 
acteristic odor  of  caoutchouc.  The  composition  of  the  oxidized- 
product  (apparently  before  removal  of  the  ozone  from  it),  was 
found,  on  careful  analysis,  to  be  C5H80. 

The  next  recorded  polymerisation  of  isoprene  was  in  1879 
when  Bouchardat  studied  the  action  of  the  haloid  acids  on  it. 
(Comptes  rendns.  80.  1117-1120).  When  dry  hydrogen  chloride 
gas  was  slowly  passed  into  isoprene  at  0°,  it  was  slowly  absorbed 
and  from  the  resulting  product  there  was  obtained  some  of  the 
unchanged  hydrocarbon  and  a  large  amount  of  the  monochlor- 
hydrate  of  isoprene,  C-IISC1.  boiling  at  86-91°.  Under  these 
conditions  (3  hrs.  action)  the  formation  of  a  substance  of  higher 
boiling  point  was  not  observed. 

On  the  other  hand,  when  saturated  hydrochloric  acid  at  0° 
acted  on  isoprene  for  15-20  hours  in  a  sealed  tube  with  occa- 
sional agitation,  and  the  resulting  product  was  distilled,  a  solid 
residue,  in  appreciable  amount,  remained  behind. 

This  solid  residue  persistently  retained  about  one  per  cent 
of  chlorine,  its  analysis  otherwise  giving  the  same  percentage 
composition  as  isoprene.  (C=87.1;  11=11.7 ;  Cl=1.7).  It  pos- 
sessed the  elastic,  and  other  characteristics  of  caoutchouc ;  it 
was  insoluble  in  alcohol,  swelled  in  ether,  and  dissolved  in  car- 
bon bisulfid  in  the  same  manner  as  natural  caoutchouc.  When 
submitted  to  dry  distillation  it  gave  the  same  volatile  hydro- 
carbons that  caoutchouc  gives.  All  these  properties  seem  to 
identify  this  isoprene  polymer  with  the  parent  material  of  the 
isoprene  itself,  caoutchouc. 


It  should  be  observed,  however,  that  in  the  above  reaction 
in  which  the  caoutchouc  was  obtained,  the  principal  products 
of  the  reaction  were  the  mono-  and  di-chlorhydrates,  while  the 
caoutchouc  was  merely  a  by-product,  constituting  not  over  one- 
sixth  of  the  resulting  product. 

Hydrobromic  acid,  in  saturated  solution,  was  found  to  act 
in  the  same  way  as  hydrochloric ;  it  formed  the  elastic  polymer 
which  retained  not  over  two  per  cent  of  bromine. 

Fuming  hydriodic  acid  acted  very  violently  on  isoprene. 
The  elastic  polymer  was  apparently  formed,  but  not  isolated. 

Tilden,  in  1882  (Chem.  News,  Vol.  46,  p.  120),  first  re- 
ported the  formation  of  isoprene  by  the  depolymerisation  of 
turpentine,  the  turpentine  vapors  being  passed  through  an  iron 
tube  heated  to  redness.  Only  20  cc.  of  the  isoprene  fraction, 
however,  were  obtained  by  this  process  from  a  liter  of  turpen- 
tine. The  isoprene  thus  obtained  was  found  to  act  in  the  same 
way  as  the  isoprene  from  caoutchouc,  and  gave  a  tough  sub- 
stance closely  resembling  caoutchouc  when  acted  on  by  con- 
centrated hydrochloric  acid.  The  conversion  of  isoprene  to 
caoutchouc  by  nitrosyl-chlorid  is  also  reported  by  Tilden  in 
this  article. 

Again  in  1884  (Trans.  Chem.  Soc,  1884,  p.  410),  Tilden 
reported  his  further  study  of  the  products  obtained  by  the 
decomposition  of  turpentine  vapors  by  heat.  As  in  the  former 
experiments  a  small  amount  of  isoprene  was  obtained  (200  cc. 
isoprene  from  4  liters  turpentine).  The  turpentine  vapors 
were  passed  through  an  iron  tube  heated  to  the  loAvest  possible 
redness  just  visible  in  a  darkened  room.  Benzene,  toluene, 
m-xylene,  cymene,  and  terpilene  were  among  the  other  prod- 
ucts identified.  About  15%  of  the  product  boiled  above  200°, 
and  was  not  further  studied.  Nearly  30%  of  the  product  was 
lost  in  the  form  of  gas.  If  the  iron  tube  in  these  experiments 
was  heated  to  visible  redness  or  to  a  higher  temperature  iso- 
prene was  no  longer  found  in  the  products  formed.  It  does 
not  appear  that  a  yield  of  as  high  as  10%  of  isoprene  was  ever 
obtained  by  this  process  (Tilden,  India-Rubber  Jour.,  36  (1908). 
p.  322).  This  isoprene,  as  in  the  case  of  the  preceding  experi- 
ments, was  converted  into  caoutchouc  by  polymerisation,  con- 
tact with  strong  acids  in  the  cold  effecting  the  change. 

In  1885  Wallach  (Annalen  der  Chemie,  238,  p.  88),  found 
that  isoprene,  when  it  remained  placed  in  the  light  for  a  long 
time,  polymerised,  and  on  adding  alcohol  to  the  resulting 
product  there  separated  out  a  caoutchouc-like  mass  which  hard- 
ened on  exposure  to  the  air. 

Apparently  unaware  of  "Wallach 's  experiments  Tilden  in 

200  THE   ARMOUR  ENGINEER  [May,  1911 

1892  (Chem.  News,  Vol.  5,  p.  265)  reported  a  similar  observa- 
tion of  the  spontaneous  polymerisation  of  isoprene  in  the  fol- 
lowing language 

"I  was  surprised  a  few  weeks  ago  at  finding  the  contents 
of  the  bottles  containing  isoprene  from  turpentine  entirely 
changed  in  appearance.  In  place  of  a  limpid  colorless  liquid 
the  bottle  contained  a  dense  syrup,  in  which  was  floating  sev- 
eral large  masses  of  solid  of  a  yellowish  color.  Upon  examina- 
tion this  turned  out  to  be  india-rubber.  The  change  of  isoprene 
by  spontaneous  polymerisation  has  not  to  my  knowledge  been 
observed.  I  can  only  account  for  it  by  the  hypothesis  that  a 
small  quantity  of  formic  or  acetic  acid  had  been  produced  by 
the  oxidising  action  of  the  air,  and  that  the  presence  of  this 
compound  had  been  the  means  of  transforming  the  rest.  The 
liquid  was  acid  to  test  paper,  and  yielded  a  small  portion  of 
unchanged  isoprene. 

"The  artificial  indiarubber,  like  natural  rubber,  appears 
to  consist  of  two  substances,  one  of  which  is  more  soluble  in 
benzene  or  in  carbon  bisulfid  than  the  other.  A  solution  of 
the  artificial  rubber  in  benzene  leaves  on  evaporation  a  residue 
which  agrees  in  all  characters  with  a  similar  preparation  from 
Para  rubber.  The  artificial  rubber  unites  with  sulfur  in  the 
same  manner  as  ordinary  rubber,  forming  a  tough  elastic  com- 

Tilden's  observations  of  the  spontaneous  polymerisation  of 
isoprene  were  later  confirmed  by  Weber  (Jour.  Soc.  Chem.  Tnd., 
1894,  Vol.  13.  p.  11).  From  300  gms.  of  isoprene  Weber  ob- 
tained, after  nine  months  standing,  and  by  treatment  of  the 
resulting  viscid,  treacly  mass  with  alcohol,  a  solid  spongy  sub- 
stance of  almost  white  color,  which  on  drying  became  a  light 
brown  and  was  in  all  respect  identical  with  indiarubber.  The 
weight  of  indiarubber  thus  obtained  was  211  gms.  The  prin- 
cipal by-products  were  dipentene  and  polyterpenes.— products 
of  very  little  value. 

Again  in  190G  (Chem.  News,  94.  p.  90)  Tilden  reports  that 
the  spontaneous  polymerisation  of  isoprene  to  caoutchouc  takes 
place  slowly,  requiring  several  years.  He  further  states  that 
if  any  attempt  be  made  to  hasten  the  operation,  as  by  heat,  or 
contact  with  strong  reagents,  the  pTeater  part  of  the  hydro- 
carbon is  converted  into  dipentene,  and  a  mixture  of  viscid 
compounds  of  high  boiling  points  known  as  colophene, — the 
same  product  as  results  from  the  polymerisation  of  the  ter- 

To  the  same  effect  is  a  further  communication  from  Tilden 

Vol.  Ill,  No.  21  SYNTHETIC  CAOUTCHOUC  :  BARROWS  201 

in  the  India-Rubber  Journal,  Vol.  36  (1908),  pp.  321-2.  A 
review  is  here  given  of  his  prior  experiments  to  date,  together 
with  a  letter  from  which  the  following  is  excerpted, — 

"The  conversion  of  isoprene  into  rubber  occurs,  so  far  as 
observed,  under  two  conditions,  (1)  When  brought  into  con- 
tact with  strong  aqueous  hydrochloric  acid  or  moist  hydrogen 
chlorid  gas;  (2)  By  spontaneous  polymerisation. 

"In  the  former  case  the  amount  of  rubber  produced  is 
small,  and  it  is  only  a  by-product  attending  the  formation  of 
the  isoprene  hydrochlorides,  which  are  both  liquid.  In  the  lat- 
ter case  the  process  occupies  several  years. 

"Of  course  many  attempts  were  made  by  me  to  hasten  the 
process,  but  it  was  found  that  contact  with  any  strong  reagent, 
such  as  oil  of  vitriol,  pentachlorid  of  phosphorus,  and  others  of 
milder  character,  led  only  to  the  production  of  the  sticky  'colo- 
phene,'  similar  to  the  substance  which  results  from  the  poly- 
merisation of  the  terpenes,  and  after  a  course  of  experiments 
which  were  carried  on  for  about  two  years,  I  was  reluctantly 
obliged  to  abandon  the  subject." 

A  more  recent  process  for  the  production  of  caoutchouc 
from  isoprene  is  that  of  Harries,  India-Rubber  Journal,  May 
16,  1910,  pp.  630-1.  This  process,  together  with  the  route  which 
led  to  its  discovery,  is  described  as  follows: — 

"I  have  shown  you  that  the  insoluble  caoutchouc  can  be 
converted  into  the  soluble  form  by  boiling  with  glacial  acetic 
acid.  So  I  came  to  the  conclusion  that  an  equilibrium  occurred, 
for  whilst  caoutchouc  is  truly  depolymerised  by  acetic  acid, 
then,  however,  it  is  equally  reconverted  into  rubber.  From  this 
point  of  view  I  likewise  heated  isoprene  with  glacial  acetic 
arid,  and  as  it  is  very  volatile  J.  employed  a  closed  tube.  I  now 
observed  that  rather  over  100°^  a  product  separates  which  is 
actually  rubber.  It  was  noticeable  That  pure  synthetic  isoprene 
is  polymerised  more  readily  than  natural  isoprene  from  rubber. 
Later  I  found  yet  other  methods.  If  the  conditions,  however, 
are  not  strictly  adhered  to,  all  sorts  of  thick  greasy  oils,  resins 
and  gums  are  obtained,  which  are  not  rubber.  *  *  *  The 
artificial  rubber  is  quite  as  tough  and  elastic  as  the  natural 
product,  and  of  a  light  brown  to  a  white  color." 

The  ozonide  and  nitrosite  formed  from  this  synthetic  rub- 
ber also  corresponded  with  those  from  natural  rubber. 

Another  report  of  the  spontaneous  polymerisation  of  isoprene 
to  caoutchouc  was  made  by  Pickles  in  1910  (Trans.  Chem.  Soc, 
June,  1910,  pp.  1086-7).  the  polymerisation  having  been  effected 
by  standing,  for  the  greater  part  of  the  time  in  the  dark,  for 
three  and  a  half  years.    All  the  numerous  tests  applied  to  the 

202  THE   ARMOUR  ENGINEER  [May,  1911 

product  thus  obtained,  and  separated  from  the  viscous  poly- 
merised mass  by  alcohol,  identified  it  as  the  same  in  composi- 
tion and  properties  as  natural  caoutchouc. 

Lebedeff,  in  a  still  more  recent  article,  to  be  hereinafter 
referred  to  more  at  length,  has  obtained  the  caoutchouc  poly- 
mer from  isoprene  by  heating  in  a  closed  vessel  at  150°  for 
several  days. 

Turning  now  from  the  periodical  to  the  patent  literature, 
we  find  that  the  first  patent  for  synthetic  rubber  was  the  Br. 
patent  to  St.  George,  15,  544,  of  1892.  According  to  this  patent 
turpentine  vapors  are  passed  through  a  heated  tube  and  con- 
densed by  a  spray  of  hydrochloric  acid ;  or  the  vapors  are  con- 
densed and  then  agitated  with  hydrochloric  acid  to  give  the 
solid  caoutchouc.  In  the  light  of  Tilden's  experiments  it  is 
probable  that  isoprene  was  formed  in  this  process  as  an  inter- 
mediate product. 

The  Heinemann  patents,  Br.  21,772  of  1907,  and  French 
394,795,  describe  the  condensation  of  isoprene  to  caoutchouc  by 
concentrated  hydrochloric  acid.  According  to  these  patents 
acetylene  and  ethylene,  when  passed  through  a  heated  tube, 
give  divinyl,  which  is  converted  into  methyl  divinyl  or  isoprene 
by  treatment  with  methyl  chlorid ;  or  the  three  gases  may  be 
passed  through  the  tube  together  to  effect  the  same  result. 

A  still  more  recent  patent  for  the  production  of  caoutchouc 
from  isoprene  is  the  French  patent  417,170,  to  the  Badische 
Anilin  &  Sodafabrik,  according  to  which  isoprene  is  heated 
either  alone  for  20  hours  at  120°,  or  with  10%  of  its  weight  of 
cone,  caustic  soda  at  100°.  The  caoutchouc  is  separated  by 
precipitation  with  alcohol,  or  by  steam  distillation  of  the  un- 
changed isoprene. 

The  hydrocarbon,  next  to  isoprene  in  point  of  interest  in 
connection  with  synthetic  rubber,  is  diisopropenyl,  or  the  2.3- 
dimethyl-1.3-butadien,  CH2:C(CH8).C(CH3)  :CH2. 

Couturier  in  1892  (Annales  de  Chimie,  6  Ser..  Vol.  26,  p. 
489)  described  this  hydrocarbon  in  the  following  language,  the 
hydrocarbon  having  been  obtained  in  small  amount  by  the  de- 
hydration of  pinacone. 

"Beta-bipropenyl  polymerises  with  extreme  ease.  *  *  * 
This  property  renders  all  reactions  with  this  hydrocarbon  diffi- 
cult. The  polymerisation  is  effected  by  heat  alone,  and  the 
liquid  is  transformed  into  a  viscous  product  which  does  not 
distill.  Chloride  of  calcium  acts  even  without  heating,  when 
left  for  a  long  time  in  contact  with  the  hydrocarbon." 

With  sulfuric  acid  Couturier  obtained  resinous  polymers. 
The  preceding  brief  description  is  valuable  as  indicating 

Vol.  Ill,  No.  2]  SYNTHETIC  CAOUTCHOUC  :  BARROWS  203 

the  peculiar  properties  of  the  hydrocarbon.  Of  even  more  in- 
terest, however,  are  the  two  articles  by  Kondakoff  in  Journal 
fiif  praktische  Chemie,  62  (1900),  p.  175,  and  64  (1901),  p.  109. 
The  first  of  these  articles  describes  the  heating  of  the 
hydrocarbon  with  alcoholic  potassium  hydroxide  (l:KOH, 
3  :EtOH)  to  150°  for  5  hours.  A  part  of  the  hydrocarbon  re- 
mained unchanged ;  a  part  was  polymerised  to  a  white  leathery 
elastic  mass,  insoluble  in  water,  but  soluble  in  hydrocarbons, 
ether  and  alcohol,  and  which  did  not  distill  with  steam.  The 
similarity  of  this  product  to  caoutchouc  was  noted. 

Again  in  the  second  article  Kondakoff  records  a  similar 
polymerisation  of  this  same  hydrocarbon,  by  letting  it  stand  in 
a  closed  bottle  in  diffused  light  for  about  a  year.  The  hydrocar- 
bon in  this  case  was  completely  converted  into  a  solid  white 
spongy  mass.  Under  the  microscope  this  mass  appeared  amor- 
phous; it  was  tasteless  and  odorless  and  as  elastic  as  caout- 
chouc. It  did  not  appear  to  undergo  change  in  the  air  and  was 
entirely  insoluble  in  benzene,  ligroin.  chloroform,  carbon  bisul- 
fid,  ether,  alcohol,  acetone  and  oil  of  turpentine,  swelling  only 
in  benzene.  The  author  observed  that  this  polymer  appeared 
to  be  a  higher  product  of  polymerisation  than  the  one  referred 
to  in  the  preceding  article. 

The  polymerisation  of  this  same  hydrocarbon  into  its 
caoutchouc-like  polymer  has  also  been  effected  by  heating  for 
several  days  under  pressure.  An  account  of  such  polymerisa- 
tion is  reported  by  Lebedeff  in  the  article  referred  to*  below. 

The  most  recent  publications  on  the  polymerisations  of  this 
hydrocarbon  (diisopropenyl)  are  the  Br.  patent  14,281  of  1910, 
and  the  French  patent  417,768  (See  the  India-Rubber  Jour., 
Feb.  4,  1911,  p.  14,  and  Gummi  Ztg.,  Feb.  10,  1911,  p.  702,  re- 
spectively), to  the  Badische  Anilin  &  Sodafabrik,  according  to 
which  the  hydrocarbon  is  polymerised  by  heating,  either  alone 
or  with  the  addition  of  such  indifferent  agents  as  water,  a  solu- 
tion of  common  salt,  or  alcoholic  caustic  potash.  After  the 
polymerisation  any  unchanged  hydrocarbon  is  distilled  off  with 
steam.  The  product  is  a  white  elastic  substance,  soluble  in 
benzene,  from  which  it  is  precipitated,  unchanged,  by  alcohol, 
and  it  possesses  the  typical  properties  of  caoutchouc. 

Closely  related  to  isoprene  and  to  diisopropenyl,  being  in 
fact  the  mother  substance  of  them,  is  erythrene,  or  divinyl,  the 
1.3-butadien,  CH,  :CH.CH  :CH.,.  British  patent  15,254  of  1909 
(Gummi  Ztg.,  Nov.  18,  1910,  p.  261)  to  the  Farbenfabriken 
vorm.  Fr.  Bayer  &  Co.  of  Elberfeld  describes  the  polymerisa- 
tion of  this  hydrocarbon  to  caoutchouc,  the  conversion  being 
effected  by  heating  under  pressure  either  alone  or  with  the  ad- 

204  THE  ARMOUR   ENGINEER  [May,  1911 

dition  of  a  reagent  which  assists  in  the  polymerisation.  Lebe- 
deff  has  also  studied  this  hydrocarbon  and  its  caoutchouc  poly- 
mer, the  polymerisation  having  been  effected  in  a  similar  man- 
ner, by  heating  at  150°  in  a  sealed  tube  for  several  days.  The 
polymerisation  of  this  hydrocarbon  is  also  briefly  referred  to  in 
Chemiker  Ztg.,  Feb.  7,  1911,  p.  63,  and  it  is  here  observed  that 
the  polymerisation  takes  place  much  more  readily  with  this 
hydrocarbon  than  with  isoprene. 

Another  hydrocarbon  belonging  to  the  same  group  as  the 
preceding,  and  closely  related  to  isoprene  (beta-methyldivinyl) 
is  piperylene  or  the  alpha-methyldivinyl.  CH,.CH:CH.CH:CH0. 
Thiele  (Annalen  der  Chemie,  319  (1901),  p.  227,  has  found  that 
this  hydrocarbon  also,  after  several  months  standing  in  the 
dark,  gives  "a  very  small  amount  of  a  rubber-like  (gummiarti- 
gen)  substance,  probably  a  polymerisation  product."  Most  of 
the  hydrocarbon  in  this  experiment,  however,  remained  with 
its  boiling  point  unchanged. 

The  intimate  relation  to  each  other  of  the  four  hydrocar- 
bons which  have  been  described,  and  from  which  synthetic 
caoutchouc  has  been  obtained,  will  be  much  clearer  from  a 
comparison  of  their  structural  formulae, — 

CH2  CH2  CH-CH3  CH„ 

C-H               C-CH3           C-H  C-CH3 


C-H  C-H  C-H  C-CH3 


CH2  CH2  CH2  CH2 

Erythrene,  Isoprene,  Piperylene,  Diisopropenyl, 

divinyl,  or  2-methyldivinyl,  1-methyldivinyl,     2.3-dimethyl- 

1.3-butadien.  or  2-methyl-1.3-    or  l-methyl-1.3-     divinyl,  or 

butadien.  butadien.  2.3-dimethyl- 


It  will  be  seen  that  all  four  of  these  hydrocarbons  belong 
to  the  divinyl  series,  containing  the  following  common  nucleus, 
C:C.C:C,  and  having  respectively  the  empirical  formulae 
C4H6,  C5H8,  C5H8,  and  C6H10.  It  is  known  that  the  caoutchouc 
from  isoprene  has  the  same  percentage  composition,  and  hence 
empirical  formula,  as  natural  caoutchouc,  viz.:  (C10Hlfi)n.  It 
should  follow,  since  the  formation  of  synthetic  caoutchouc  is 
by  a  polymerisation  reaction,  that  the  caoutchoucs  from  ery- 
threne, piperylene,  and  diisopropenyl  should  also  have  the  same 
empirical  formulae  as  the  hydrocarbons  from  which  derived,  or 
(C8H12)„,  (C10H16)n,  and  (C12H20)„,  respectively.  Such  formulae 
are  also  indicated  by  the  ozonides  referred  to  below. 

A  valuable  contribution  to  the  literature  on  the  subject  of 


these  diethylenic  hydrocarbons  (containing  the  nucleus 
C:C.C:C)  is  an  article  by  Lebedeff  dealing  with  their  autopoly- 
merisation  found  in  the  Journal  of  the  Russian  Physical-Chemi- 
cal Society,  1910,  Vol.  42,  No.  6,  p.  949.  According  to  this  arti- 

"The  polymerisation  of  these  hydrocarbons  takes  place  in 
such  a  typical  manner  that  it  may  be  considered  a  general  char- 
acteristic of  the  whole  group.  The  rapidity  of  the  process, 
sometimes  exceedingly  slow  at  normal  temperatures,  increases 
very  rapidly  with  rising  temperature." 

The  polymerisation  of  the  three  hydrocarbons,  erythrene, 
isoprene,  and  diisopropenyl  was  investigated  in  detail  by  Lebe- 
deff, a  caoutchouc  polymer  being  obtained  from  each.  The 
polymerisation  was  effected  by  heating  in  a  sealed  tube  at  150°, 
the  process  requiring  6  to  7  days  for  its  completion  in  the  case 
of  erythrene,  and  8  to  10  days  in  the  case  of  isoprene  and  diiso- 
propenyl. Ozonides  were  formed  from  each  of  these  polymers, 
the  ozonides  derived  from  the  erythrene,  isoprene  and  diiso- 
propenyl polymers  having  the  formulae  C8H1206,  C10H16O6,  and 
C12H20O6,  and  yielding  on  decomposition  with  water  succinic 
aldehyde,  laevulinic  aldehyde,  and  acetonylaceton  respectively. 
To  these  ozonides,  therefore,  the  following  structural  formulae 
were  assigned, — 

HC         CHt  HC       ^CH        CH-C         CH, 

I.  I.  M. 

The  ozonide  reactions  of  caoutchouc  are  particularly  valua- 
ble because  of  the  light  they  throw  on  the  constitution  of  the 
caoutchouc  molecule. 

Two  theories  as  to  the  constitution  of  this  molecule  have 
thus  far  been  proposed.  In  view  of  the  importance  of  the  sub- 
ject to  which  they  relate  it  is  desirable  to  examine  these  theo- 
ries in  detail.  The  first  is  the  cyclooctadiene  theory  of  Harries ; 
the  other  is  that  proposed  as  an  alternative  by  Pickles  before 
the  British  Association  last  year.  The  former  theory  is  given  is 
two  articles  appearing  in  No.  36  of  the  Gummi  Ztg.,  March, 
1910,  and  Chemiker  Ztg.,  1910,  March  26,  p.  815,  and  translated 

206  THE  ARMOUR  ENGINEER  [May,  1911 

into  the  India-Rubber  Journals  of  June  13,  1910,  p.  772,  and 
May  16,  1910,  p.  630,  respectively.  The  following  is  excerpted 
from  the  first  of  these  articles, — 

"As  I  will  subsequently  show,  rubber  is  to  be  regarded  as 
a  polymerisation  product  of  a  hydrocarbon  (C10H16)  with  a 
ring-like  arrangement  of  eight  carbon  atoms.  It  might  be  as- 
sumed that  by  suitably  strong  depolymerisation  treatment  it 
would  be  possible  to  reduce  the  rubber  to  such  a  hydrocarbon. 
I  have  found  that  depolymerisation  can,  in  fact,  be  effected, 
especially  by  long  boiling  of  the  rubber  in  toluol  or  xylol.  How- 
ever, the  actual  product  which  should  be  first  produced,  ac- 
cording to  my  theory,  is  not  obtained,  probably  on  account 
of  its  instability,  but  in  its  place  allied  compounds,  such  as 
dipentene  and  other  hydrocarbons  resembling  turpentine.  The 
fact,  however,  that  rubber  is  depolymerised  by  protracted  boil- 
ing in  solvents  of  high  boiling  points  is  of  importance  for  the 
question  of  the  determination  of  its  constitution.  Regarding  its 
molecular  weight  we  know  nothing  definite ;  the  experiments 
undertaken  lately  by  Henrichsen  cannot  be  regarded  as  de- 

Caoutchouc  is  a  hydrocarbon  of  the  empirical  formula 
C10Ht6;  it  is  optically  inactive,  and  has  therefore  no  asymmet- 
rical carbon  atom.  By  bromination  it  takes  up  four  atoms  of 
bromine  and  accordingly  possesses  two  ethylene  linkings.  Dis- 
solved in  choloroform  and  treated  with  ozone  two  molecules  of 
ozone  are  added ;  and  being  readily  soluble  the  formula  of  this 
so-called  diozonide  can  be  determined;  it  is  C10Hlf.Ofi.  At  the 
same  time  the  ozone  treatment  causes  a  depolymerisation  of  the 
high  rubber  molecule.  On  boiling  this  diozonide  with  water  it 
decomposes  into  laevulinic  aldehyde,  laevulinic  acid,  and  a 
crystalline  body  which  I  have  named  laevulinic  aldehyde  diper- 

C10H1(A  =  CH3.CO  .CH2.CH2.CHO 
and  CH,.C0„.CH.,.CHo.CH0., 

''From  this  it  would  appear  that  caoutchouc  ozonide  must 
contain  an  eight  carbon  ring,  for  the  ozone  is  situated  at  the 
ethylene  linkings,  and  in  splitting  up,  division  of  the  molecule 
occurs  at  the  positions  where  the  ozone  has  entered,  with  the 
formation  of  compounds,  aldehydes,  or  acids,  containing  oxy- 
gen.   "We  come  then  to  the  following  graphic  formulae : — 




HX      0»p»rc?xid»  CH2 

-C^  Laevui/rvi'c 



and  the  hydrocarbon  which  forms  the  basis  of  the  caoutchouc 
molecule,  and  by  the  polymerisation  of  which  the  same  is  pro- 
duced : — 



"*  CH, 

1:5-  dim«<t"hylcycloo£Tz»diene  (1:5) 

Before  I  showed  that  in  all  probability  the  eight  carbon 
ring  occurs  in  caoutchouc,  this  carbon  combination  had  not  been 
discovered  in  nature.  Shortly  afterwards  Willstaetter  found 
an  alkaloid  in  the  root  of  the  pomegranate,  having  likewise  an 
eight  carbon  ring  combination,  and  eventually  he  built  up 
therefrom  the  lower  homologue,  which  forms  the  basis  of  rub- 
ber chemistry.  From  this  hydrocarbon,  cyclo-octadiene,  I  have 
proved  that  the  two  ethylene  linkings  are  situated  in  1 :5  posi- 
tion as  caoutchouc,  for  it  yields  in  the  splitting  up  with  ozone, 
succinic  aldehyde. 







Succinic    aldeKyde^ 

On  heating  to  70°C.  this  cyclo-octadiene  is  polymerised, 
and  under  special  conditions  I  obtained  therefrom  a  product 
extraordinarilv  similar  to  rubber.     *     *     * 

208  THE   ARMOUR  ENGINEER  [May,  1911 

All  attempts  to  extract  the  two  molecules  of  ozone  from 
caoutchouc  by  suitable  reduction,  and  even  to  regenerate  the 
hydrocarbon,  have  hitherto  failed ;  its  synthesis  also  has  not 
been  accomplished." 

Again  in  the  India-Rubber  Journal  of  May  16,  1910,  in 
discussing  the  formation  of  caoutchouc  from  isoprene, — 

"In  seeking  to  discover  how  the  reaction  occurs  in  the 
polymerisation,  the  conclusion  is  reached  that  isoprene  first 
changes  into  dimethylcyclooctadiene,  with  condensation  at 
the  carbon  atoms  in  1 :4  position,  as  in  all  addition  reactions, 
results  from  bodies  with  conjugated  double  linkings. 

hL      xhw        h2c     Jrt 

"The  condensation  must  take  place  in  this  way  because 
on  oxidation  with  ozone  laevulinic  aldehyde  is  formed." 

A  conclusion  similar  to  that  reached  by  Harries  is  also 
reached  by  Lebedeff  in  his  article  above  referred  to.  This 
article,  however,  discusses  the  polymerisation  of  the  whole 
class  of  diethylenic  (C:C.C:C)  hydrocarbons,  and  from  a 
broader  aspect.  A  further  discussion  of  this  article  bearing 
both  directly  and  indirectly  on  the  constitution  of  rubber  will 
therefore  be  given.    Quoting  further  from  this  article, — 

"A  closer  examination  of  the  products  of  polymerisation, 
which  consist  of  dimers  and  polymers  of  the  diethylenic  hydro- 
carbons, shows  that  we  have  to  do  with  two  parallel  processes : 

I.  ±. 

/\    A 

|l  !!  !  p=c-c=f  C-c=C-c 



I     dimer    C  polymer 


"The  first  process  leads  to  the  formation  of  a  six-mem- 
bered  ring  with  two  double  bonds,  one  in  the  ring,  and  the 

Vol.  Ill,  No.  2]  SYNTHETIC  CAOUTCHOUC:  BARROWS  200 

other  in  the  side  chain.  The  second  process  leads  to  the  for- 
mation of  an  eight-membered  ring  with  two  double  bonds, 
closely  related  to 

(— C— C  =  C— C] 
I    C— C  =  C— Cjx 

From  a  consideration  of  the  above  proposed  system  it  is 
obvious  that  a  symmetrically  arranged  molecule  can  give  rise 
to  only  one  dimer  with  a  six-membered  ring.  Such  are  divinyl 
and  diisopropenyl.  As  a  matter  of  fact,  the  dimers  of  divinyl 
and  diisopropenyl  consist  of  only  one  hydrocarbon.  *  *  * 
An  unsymmetrically  arranged  molecule  may  give  rise  to  four 
dimers.  In  the  ease  of  isoprene  two  such  dimers  have  been 
observed;  the  other  two  it  lias  not  been  possible  to  identify. 
Those  observed  are  dipentene  and  a  hydrocarbon  of  boiling 
point  160-161°  at  760  mm.     *     *     *" 

Lebedeff's  experiments  with  erythene,  isoprene  and  diiso- 
propenyl and  the  ozonides  obtained  from  them  have  already 
been  referred  to  above.  In  discussing  the  ozonide  from  the 
isoprene  polymer  it  is  further  observed, — 

"The  system  of  polymerisation  proposed  by  me  foresees 
the  possibility  of  the  formation  of  another  isomeric  ozonide 

C  CH- 

"Whether  this  isomer  is  formed  is  not  yet  clear." 
The  non-existence,  or  the  existence  if  at  all,  only  in  very 
small  amounts,  of  such  an  isomeric  ozonide  would  seem  to  in- 
dicate strongly  that  the  unsymmetrical  position  of  the  methyl 
group  in  the  isoprene  molecule  exerts  a  marked  influence  on 
its  polymerisation.  This  lack  of  symmetry  in  hydrocarbons 
such  as  isoprene  is  indeed  mentioned  by  Lebedeff  as  one  of  the 
factors  influencing  the  polymerisation  reactions  of  these  hy- 
drocarbons. It  was  found  by  him  that  the  polymerisation  by 
light  is  much  slower  in  the  case  of  isoprene  than  in  the  case 
of  diisopropenyl.     It  is  also  interesting  to  observe  in  this  eon- 

210  THE   ARMOUR   ENGINEER  [May,  1911 

nection  that  divinyl  has  similarly  been  found  to  polymerise 
much  more  readily  than  isoprene  (Chem.  Ztg.,  above). 

The  conditions  under  which  the  polymerisation  is  effected 
are  also  mentioned  by  Lebedeff  as  influencing  the  polymerisa- 
tion reaction.  Low  temperatures  favor  the  formation  of  the 
polymer;  sunlight  seems  to  act  in  the  same  way.  Increasing 
the  temperature  facilitates  the  reaction  but  favors  the  forma- 
tion of  a  larger  amount  of  dimer.  The  reactions  appear  to  be 
equilibrium  reactions  but  the  equilibrium  exhibits  some  pecu- 
liar characteristics. 

The  dimer  and  polymer  are  not  mutually  convertible  the 
one  into  the  other,  and  the  relative  amounts  of  dimer  and  poly- 
mer remain  practically  constant  during  the  reaction  if  the 
temperature  and  other  conditions  of  reaction  remain  constant. 
This  result  is  to  be  expected  from  the  nature  of  the  two  prod- 
ucts. The  conversion  of  the  monomer  into  the  dimer  and  poly- 
mer will  also  go  to  completion  if  allowed  to  do  so,  all  the 
monomer  disappearing.  It  is  interesting  to  observe  that  the 
amount  of  dimer  formed  from  isoprene  was  larger  than  from 
the  symmetrical  diisopropenyl. 

Keturning  now  again  to  the  subject  of  the  constitution  of 
rubber,  and  taking  it  up  from  another  direction,  is  is  desired 
to  call  attention  to  the  following  conclusions  which  were 
drawn  by  Pickles  after  a  thorough  discussion  and  considera- 
tion of  the  products  of  the  pyrogenic  decomposition  of  rubber 
(Address  before  the  British  Assn.,  1906,  Reports,  p.  2-47). 

"(1)  The  rubber  hydrocarbon  is  closely  related  to  the 
terpenes,  and  any  formula  expressing  its  constitution  must 
also  be  explanatory  of  the  easy  transition  of  this  hydrocar- 
bon into  isoprene  and  dipentene. 

"(2)     The  existence  of  the  complex  C — C — C — C  must  be 


assumed  in  the  rubber  molecule,  as  it  occurs  in  all  the  exam- 
ined decomposition  products. 

"(3)  Isoprene  and  dipentene  do  not  occur  in  the  rubber 
molecule  as  such,  but  are  produced  by  the  disruption  of  a 
larger  or  more  physically  complex  molecule  at  a  high  temper- 
ature, for,  as  Fisher  and  Harries  have  shown,  if  the  distilla- 
tion is  conducted  at  as  low  a  temperature  as  possible,  these 
compounds  are  not  produced  in  any  considerable  quantity." 

Turning  now  to  the  theory  which  Pickles  has  suggested  as 
an  alternative  to  that  of  Harries,  and  which  was  published  for 
the  first  time  last  year,  the  following  is  found, — 

"Since  Harries  has  shown  that  laevulinic  aldehyde,  laevu- 
linic  aldehyde  peroxide,  and  laevulinic  acid  are  the  only  oxi- 

Vol.  Ill,  No.  2]  SYNTHETIC  CAOUTCHOUC:  BARROWS  211 

dation  products  of  caoutchouc,  the  polymerisation  of  isoprene 
into  rubber  must  be  accompanied  by  a  rearrangement  of  the 
double  bonds, 

CH2:CMe.CH:CH2  >  .CH2.CMe  :CH.CH2. 

as  on  on  other  assumption  is  the  formation  of  .laevulinic  alde- 
hyde possible. 

"As  is  well  known,  "this  re-arrangement  takes  place  in 
many  cases  where  subtsances  possessing  conjugated  ethylenic 
linkings  enter  into  chemical  combination.  It  is  suggested  that 
these  unsaturated  C5H8  nuclei  unite  to  form  long  chains  of  the 
structure : 

CH2.CMe  :CH.CH2.CH2.CMe  :CH.CH2.CH2CMe  :CH.CH2. 
and  that  the  number  of  C5H8  complexes  may  vary  in  different 
kinds  of  rubber,  the  difference  in  properties  being  probably 
due  to  this  variation  in  the  number  of  complexes  contained. 
The  oxidation  results  require  that  the  two  ends  of  the  chain 
should  be  linked  together,  which,  of  course,  leads  to  the  forma- 
tion of  a  ring,  but  it  is  proposed  that  in  each  rubber  molecule 
there  is  only  one  such  ring.  Rubber  probably  contains  at 
least  eight  C5H8  complexes  connected  as  above  indicated. 

"This  suggestion  is  put  forward  as  an  alternative  to  Pro- 
fessor Harries'  cyclooctadiene  formula,  which  is  to  a  certain 
extent  unsatisfactory,  as  its  arrangement  demands  the  employ- 
ment of  vague  and  unnecessary  conceptions  of  polymerisation. 

"For  this  view  of  the  composition  of  caoutchouc  the  as- 
sumption is  necessary  that  the  polymerisation  is  either  purely 
physical  or  that  the  connection  between  the  individual  chemi- 
cal molecules  is  of  so  loose  a  nature  as  to  allow  the  ozone  first 
to  depolymerise  the  aggregate  before  it  attaches  itself  to  the 
individual  molecules.  The  necessity  for  this  rather  vague  and 
unsatisfactory  assumption  results  from  the  acceptance  of  the 
dimethylcyclooctadiene  formula,  for  if  the  polymerisation  were 
chemical  in  character,  the  polymeride  formed  would  be  rela- 
tively less  unsaturated  than  the  C10H16  nucleus.  This,  how- 
ever, is  not  the  case,  for  rubber  contains  one  ethylenic  linkage 
for  every  C5H8  complex.  Moreover,  there  are  several  facts 
which  are  not  satisfactorily  explained  by  Harries'  formula. 
Since  ozone  effects  depolymerisation.  it  is  to  be  expected  that 
other  substances  which  tend  to  saturate  the  compound  would 
likewise  have  a  similar  primary  influence.  Bromine  should, 
therefore,  first  depolymerise  the  colloidal  molecule,  and  then 
form  simple  molecules  having  the  formula  C10H16Br4.  But  the 
properties  of  the  bromoderivative  of  caoutchouc,  and  its  gen- 

212  THE  ARMOUR  ENGINEER  [May,  1911 

eral  behavior  indicate  a  composition  probably  as  complex  as 
that  of  caoutchouc  itself. " 

Pickles  further  observes  that  nitrous  gases  act  in  a  man- 
ner similar  to  bromine,  giving  a  derivative  of  relatively  high 
molecular  weight.  Reference  is  also  made  by  him  to  Berthe- 
lof  s  experiments  in  which  on  reducing  caoutchouc  by  heating 
to  a  high  temperature  with  hydriodic  acid  hydrocarbons  of  the 
paraffine  series  were  obtained  of  a  boiling  point  much  higher 
than  would  correspond  to  bodies  of  the  formula  C,0H.J(1. 

The  above  theory  suggested  by  Pickles  is  not  as  a  whole 
entirely  satisfactory.  It  is  hard  to  conceive  of  a  molecule  with 
a  single  forty  carbon  atom  ring.  It  is  difficult  to  explain  how 
such  a  forty  membered  ring,  once  formed,  could  react  by  fur- 
ther polymerisation  or  depolymerisation.  Finally  the  existence 
of  a  small  number  of  bonds  or  valencies  of  a  much  more  re- 
active nature  than  the  rest  is  not  explained  by  such  a  theory. 
The  existence  of  such  bonds  in  rubber  is  strongly  indicated  by 
its  vulcanisation  reaction.  Weber  (Chemistry  of  India-Rubber) 
states  that  as  little  as  2  to  2.5%  of  sulfur  is  sufficient  to  effect 
complete  vulcanisation  and  that  the  resulting  vulcanised  rub- 
ber possesses  the  highest  degree  of  elasticity  and  distensibility 
combined  with  the  highest  degree  of  tensile  strength.  Rub- 
ber possessing  a  higher  coefficient  of  vulcanisation  sometimes 
shows  higher  tensile  strength,  but  at  the  expense  of  the  other 
physical  constants. 

In  summarising  the  foregoing  facts  and  theories  it  would 
seem  that  any  acceptable  theory  of  the  constitution  of  the 
caoutchouc  molecule  must  not  be  inconsistent  with  the  follow- 
ing observed  facts, — Caoutchouc  yields  on  treatment  with 
ozone  a  product  of  depolymerisation  and  addition,  caoutchouc 
ozonide ;  it  gives  on  treatment  with  bromine  a  product  of  addi- 
tion but  not  of  complete  depolymerisation,  the  so-called  tetra- 
bromide;  it  gives  on  depolymerisation  by  boiling  in  solvents 
of  high  boiling  point,  not  the  cyclooctadiene,  but  the  more 
stable  six-membered-ring  terpenes,  such  as  dipentene;  on  de- 
structive distillation  it  gives  a  series  of  products  of  widely 
varying  complexity  from  isoprene  through  dipentene  to  the 
more  complex  and  higher  boiling  products  which  result  par- 
ticularly from  vacuum  distillation;  it  is  converted  into  hydro- 
carbons of  the  paraffine  series  by  hydrogenation ;  it  may  be 
formed  by  the  polymerisation  of  isoprene  and  similar  hydro- 
carbons, but  not  from  dipentene,  and  it  may  itself  be  con- 
verted from  a  lower  to  a  higher  state  of  polymerisation  and 
vice  versa;  and  finally  it  may  be  completely  vulcanised  by  a 
very  small  amount  of  sulfur. 

Vol.  Ill,  No.  2]  SYNTHETIC  CAOUTCHOUC  :  BARROWS  213 

A  valuable  suggestion  bearing  indirectly  on  the  present 
subject  is  found  in  a  communication  by  Wechsler  in  Chem. 
News,  Vol.  100  (1910),  p.  279.  In  discussing  the  reactions  of 
bodies  containing  in  their  molecule  the  group  —  C=C— C=C — 
Wechsler  suggests  that  if  we  write  the  carbon  atoms  more 
according  to  their  relative  positions  in  space,  as  in  (I),  then, 
if  the  double  bonds  attract  each  other,  we  have  (II),  in  which 
the  end  atoms  are  much  more  open  to  attack  than  the  middle 

^        yf         /°- 

From  the  formula  (II)  suggested  by  Wechsler  it  is  but  a 
step  to  formula  (III),  which  has  been  hereinbefore  referred  to. 

If  we  apply  the  above  suggestion  to  the  long  chain  pro- 
posed by  Pickles,  and  write  the  carbon  atoms  more  according 
to  their  relative  positions  in  space,  we  would  not  expect  to 
obtain  a  single  ring  of  at  least  forty  carbon  atoms,  but  we 
would  expect  this  long  ring  to  double  back  upon  itself  at  about 
the  sixth  carbon  atom.  Then  if  the  double  bonds,  which  recur 
regularly  at  the  fourth  and  eighth  carbon  atoms,  attract  each 
other,  and  are  able  mutually  to  satisfy  each  other,  they  might 
be  expected  to  join  together  and  give  a  molecule  with  a  con- 
figuration similar  to  that  of  a  helix  or  spiral  spring, — the  con- 
tiguous alternative  double  bonds  being  thus  joined  to,  and  sat- 
isfied by,  each  other.  A  fragment  of  such  a  molecule  might  be 
represented  graphically  as  in  (A)  with  the  double  bonds 
joined  together  as  in  (B). 



a    i  1 


1  ' 

Such  a  spiral  or  helical  molecule  would  be  closely  related 
to  the  cyclooctauiene  ring,  as  will  be  apparent  from  the  follow- 
ing diagrams.    From  these  it  will  be  seen  that  the  alternative 

214  THE  ARMOUR  ENGINEER  [May.  1911 

double  bonds  are  in  practically  the  same  relative  positions 
whether  we  have  a  series  of  cyclooctadiene  rings  (B)  or  a 
spiral  (A).  An  explanation  of  the  eight  membered  ring,  or  a 
structure  closely  related  to.  it,  is  thus  made  possible  by  the 
modifying  action  of  these  contiguous  alternative  double  bonds. 

Such  a  spiral  molecule  could  form  the  tetrabromide  by  ad- 
dition of  bromine  at  each  double  bond  without  depolymerisa- 
tion;  it  could  break  completely  at  each  alternative  double 
bond  with  rearrangement  of  the  ring  to  give  the  stable  six- 
carbon-ring  terpenes ;  it  could  break  at  each  alternative  double 
bond  in  a  different  manner  to  give  the  ozonide;  on  pyrogenic 
decomposition  by  heat  this  molecule  might  break  at  any  of  its 
double  bonds  to  give  products  of  varying  complexity,  but  all 
having  the  empirical  formula  (C5H8)x;  by  hydrogenation  such 
a  molecule  might  be  expected  to  give  a  saturated  hydrocarbon 
of  the  paraffine  series.  It  is  proposed  that  the  bonds  at  the 
ends  of  such  a  molecule  are  free,  or  relatively  free,  so  that  this 
molecule  can  further  react  to  give  a  more  highly  polymerised 
product;  and  it  is  further  proposed  that  by  the  saturation  of 
these  bonds  by  sulfur  vulcanisation  is  effected. 

This  theory  requires  that  the  spiral  molecule  have  its  alter- 
native double  bonds  joined  together  and  saturated  bj7  each 
other,  but  joined  in  such  a  manner  that  upon  treatment  with 
suitably  strong  reagents  addition  may  take  place  much  as  if 
the  double  bonds  still  exist  in  a  modified  and  less  reactive 

The  spiral  or  helical  theory  above  suggested  has  not,  to 
the  knowledge  of  the  present  writer,  heretofore  been  published. 
It  is  with  not  a  little  hesitation  that  it  is  offered  at  this  time. 
But  if  it  shall  aid  even  a  little  in  the  ultimate  solution  of  the 
nature  of  the  rubber  molecule  its  object  will  have  been  accom- 


By  M.  S.  FLINN,  M.  E.* 

In  the  manufacture  of  many  products  heating  operations 
are  involved  which  combine  to  make  up  a  considerable  part  of 
their  ultimate  cost,  and  for  the  reason  that  competition  is  only 
met  profitably  when  operating  and  manufacturing  factors  are 
reduced  fco  the  lowest  point,  economy  is  and  undoubtedly  will 
continue  to  be  the  watchword  of  successful  industry.  Until 
rather  recently  little  or  no  attention  was  directed  towards  ef- 
fectually cutting  down  the  expense  incident  to  forging,  hard- 
ening, tempering,  japanning  and  such  operations.  It  is  also 
of  considerable  interest  to  know  that  never  in  the  history  of 
manufacturing  endeavor  have  the  demands  for  quality  and 
strength  of  material  been  so  strict  as  at  the  present  time — the 
advent  of  the  automobile,  to  a  great  extent,  being  responsible 
for  this. 

In  the  heat  treatment  of  steel  great  progress  has  been 
made  in  ascertaining  temperature  conditions  which  will  pro- 
duce definite  effects  in  regard  to  its  structure.  It  has  become 
the  practice  in  many  factories  to  submit  the  steel  parts  to  va- 
rious heating  operations  in  order  to  make  them  physically  able 
to  withstand  the  ultimate  wear  and  tear  they  will  undergo 
when  assembled  and  have  become  the  working  parts  of  a 
greater  mechanism. 

The  several  fuels  with  which  the  manufacturer  generally 
comes  in  contact,  together  with  their  respective  heating  values. 
are : — 

Wood    6,000  B.  T.  IL  £er  I  pound. 

Bituminous  coal    13,000  B.  T.  U.  per  1  pound. 

Anthracite    coal    12,500  B.  T.  U.  per  1  pound.- 

Fuel    oil    140,000  B.  T.  U.  per  gallon. 

Gasoline  and  naphtha   .  .  .125,000  B.  T.  U.  per  gallon. 

Natural  gas   1,000  B.  T.  U.  per  eu.  ft, 

Carbureted  water  gas  ...        600  B.  T.  U.  per  cu.  ft. 

Coal  gas    625  B.  T.  U.  per  cu.  ft. 

Water  gas    300  B.  T.  IT.  per  cu.  ft. 

Raw   bituminous   producer 

gas    (hot)    250  B.  T.  U.  per  cu.  ft. 

Anthracite    producer    gas 

(cold)     145  B.  T.  IT.  per  cu.  ft. 

The  heat  values  given  are  necessarily  approximate  on  ac- 
count   of    the    variable    nature    of    the    fuels,    but    they    indi- 

*Class  of  1904.     Secretary  ami  Treasurer.  Flinn  &  Dreffein  Co..  Engineers  and 
Manufacturers,   Chicago. 

216                                  THE  ARMOUR  ENGINEER                      [May,  1911 

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Fig.    1.      Curves    showing    Relative    Efficiency    of    Several    Fuels    at    Various 
Furna.ce   Temperatures, 

Vol.  Ill,  No.  2]   ANTHRACITE  PRODUCER  GAS  :  FLINN  21" 

cate  a  fair  average.  This  is  a  formidable  list  from  which  one 
has  to  choose ;  however,  they  may  he  classified  as  1st,  Solid ; 
2nd,  Liquid ;  3rd,  Gas.  There  exists  a  definite  relation  between 
each  and  every  one  of  them  from  which  comparative  costs  can 
be  readily  established.  The  relations  in  turn  are  affected  by 
the  nature  of  heating  work  they  are  to  perform. 

Heating  operations  may  be  divided  into  three  classes:  1st, 
Low  temperature;  2nd,  Medium  temperature,  and  3rd,  High 
temperature.  For  low  temperature  operations  the  relations  be- 
tween the  various  fuels  are  almost  proportional  to  their  respec- 
tive B.  T.  U. ;  however,  for  higher  temperatures  this  is  not  the 
case.  In  other  words  since  natural  gas  has  a  heat  value  of 
about  1.000  B.  T.  U.  per  cu.  ft.  and  anthracite  producer  gas 
150  B.  T.  U.  per  cu.  ft.  it  would  seem  that  6V2  cu.  ft.  of  pro- 
ducer gas  will  do  the  equivalent  heating  work  of  1  cu.  ft.  of 
natural  gas,  regardless  of  the  temperature  demanded  by  the 
operation.  For  low  temperatures  this  holds  very  nearly  true, 
but  at  high  temperatures  a  greater  quantity  of  producer  gas  is 
required  to  equal  a  cubic  foot  of  natural  gas.  The  reason  for 
this  is  that  the  flame  temperature  of  natural  gas  is  higher  than 
that  of  producer  gas,  being  about  3,700  deg.  F.  and  2,700  deg. 
F.  respectively,  under  ordinary  conditions,  where  air  is  used 
to  support  combustion. 

The  flame  temperature  resulting  from  combustion  depends 
upon  the  heat  evolved  by  the  chemical  reactions  and  the  spe- 
cific heat  of  the  products  of  combustion.  Numerically,  the 
flame  temperature  equals  the  heat  units,  evolved  by  the  fuel, 
divided  by  the  product  of  the  combustion  gases  and  their  spe- 
cific heat.  Tt  is  the  ratio  then  of  the  B.  T.  U.  of  a  unit  of  fuel 
to  the  products  of  combustion  times  its  specific  heat,  and  as  the 
excess  air  for  combustion  is  increased,  so  is  the  flame  tempera- 
ture decreased.  Again,  in  a  fuel  containing  elements  not  as- 
sisting combustion  the  same  result  occurs — for  instance,  a  gas 
carrying  proportions  of  carbon  dioxide  and  nitrogen.  Con- 
sideration of  these  facts  must  be  taken  in  comparing  fuels  for 
various  heating  operations. 

The  curves  in  Fig.  1  show  in  per  cent  the  available  heat 
that  can  be  obtained  from  the  various  fuels  when  properly 
burned  under  practical  conditions.  Tt  will  be  observed  that 
the  several  curves  converge  as  the  temperatures  of  the  furnace 
operations  decrease.  In  other  words,  for  such  work  as  japan- 
ning, baking  and  the  like,  where  a  temperature  in  the  neigh- 
borhood of  500  deer.  Fah.  is  necessary,  a  B.  T.  IT.  in  one  fuel 
will  go  very  nearly  as  far  as  a  B.  T.  TT.  in  another.  As  the 
temperature  demands  increase  for  hardening,  tempering,  an- 



[May,  1911 

nealing,  and  the  like,  the  efficiency  of  the  poorer  fuels — as,  for 
instance,  producer  gas — falls  off  so  that  for  an  operation  de- 
manding 2,000  deg.  Fah.  the  available  heat  in  producer  gas  is 
about  28%  as  compared  with  44%  in  carbureted  water  gas. 
Therefore,  the  ratio  between  44  and  28  (or  1.57  B.  T.  XL),  is 
necessary  in  producer  gas  to  produce  the  same  heating  effect 
as  1  B.  T.  U.  in  the  carbureted  water  gas. 

The  use  of  solid  fuel  in  connection  with  furnaces  is  rapidly 
being  displaced  by  the  adoption  of  gas.  The  latter  permits 
flexibility  of  operation  unapproached  by  solid  fuel,  for  the 
reason  that  by  the  simple  manipulation  of  valves  higher  or 



Fig.   2.     Extension   View    of   Anthracite   Producer   Gas   Plant   for   Heating 

lower  temperatures  can  be  obtained.  Very  nearly  theoretical 
mixtures  of  gas  and  air  can  be  used,  thus  effecting  high  com- 
bustion efficiencies,  whereas  with  solid  fuels  large  excess  of 
air  is  required.  Many  heating  ovens  are  provided  with  thermo- 
static devices  which  automatically  maintain  the  desired  tem- 

The  introduction  of  producer  gas  for  heating  operations 
invites  a  consideration  of  this  fuel  in  regard  to  its  economy  as 
compared  with  other  fuels  used  in  existing  practice.  The  fol- 
lowing is  a  description  of  the  producer  gas  equipment,  manu- 
factured by  Flinn  &  Dreffein  Co.,  Chicago,  for  use  in  connec- 



tion  with  industrial  heating  operations.  Referring  to  the  ex- 
tension view  shown  in  Fig.  2,  from  left  to  right  the 
apparatus  consists  principally  of,  1st,  GENERATOR;  2nd, 
Coal  is  converted  into  gas  in  the  generator.     Gas  leaving  the 


Sectional  Elevation   of  Anthracite   Water  Sealed  Generator. 

generator  passes  through  the  economizer  where  it  gives  up  most 
of  its  heat,  then  through  the  scrubber  where  the  soot,  tar,  and 
other  impurities  are  removed,  and  lastly  compressed  by  the 
exhauster  and  delivered  to  the  gas  mains. 

Producer  gas  is  made  from  the  cheaper  grades  of  anthra- 
cite coal,  such  as  No.  1  buckwheat  and  pea  sizes.  The  gas 
making  process  takes  place  in  the  generator,  where  a  fuel  col- 
umn about  30"  deep,  in  the  course  of  combustion,  rests  on  a 
layer  of  ash  about  8"  deep,  both  being  supported  by  the  shak- 



[May,  1911 

ing  grate.  The  ash,  of  course,  is  inert  and  merely  acts  as  an 
insulation  for  the  grate.  Air,  previously  heated  in  the  econo- 
mizer and  carrying  with  it  steam,  is  supplied  to  the  fuel  column 
from  underneath  the  grate,  When  the  air  and  steam  enter  and 
come  in  contact  with  the  hot  coal  (carbon),  combustion  takes 
place  by  the  oxygen  of  the   air  combining  with   the  carbon. 

Fig.  4. 

Small  Producer  Gas  Plant  for  Supplying  Gas  to  Soldering  and  Japan- 
ning  Ovens    in   a    Lantern    Factory. 

In  the  presence  of  hot  carbon,  oxygen  has  a  greater  affinity 
for  carbon  than  for  hydrogen ;  so,  as  the  steam  comes  in  contact 
with  the  hot  fuel  it  breaks  up,  the  hydrogen  passing  up  as  a 
gas  and  the  oxygen  supporting  the  combustion  of  more  carbon. 
At  this  stage  three  distinct  gases  are  liberated :  1st,  Carbon 
dioxide  (C02),  formed  by  the  union  of  carbon  and  oxygen  and 
representing  products  of  complete  combustion;  2nd,  Hydrogen 



(H)  liberated  from  the  steam;  3rd,  Nitrogen  (N)  carried  in 
with  the  air.  The  latter,  being  an  inert  gas,  neither  assists  nor 
interferes  with  the  reactions. 

These  three  gases  continue  upwards  through  the  hot  fuel 
column.  The  hydrogen  and  nitrogen  are  permanent  fixtures 
in  the  ultimate  producer  gas,  but  the  carbon  dioxide  is  acted 
upon  further.     In  the  presence  of  hot  carbon,  carbon  dioxide 

Tig.    5.      Small    Producer    Gas    Plant    showing    Generator,    Economizer    and 
Scrubber.      Coal    is    Stored    in    Bunkers    Above    Plant. 

picks  up  another  atom  of  carbon  forming  carbon  monoxide 
(CO),  the  reaction  expressed  chemically  being  C02  +  C  =  2CO. 
Carbon  monoxide  is  a  combustible  gas  and  forms  a  large  pro- 
portion of  producer  gas.  This  completes  the  chemical  reactions 
which  result  in  producer  gas,  although  an  additional  compo- 
nent is  methane  or  marsh  gas  (CHJ  which  is  present  in  small 

222  THE  ARMOUR  ENGINEER  [May,  1911 

quantities.     This,  however,  is  driven  off  from  the  coal  by  the 
heat  in  the  generator. 

If  air  only  were  used  in  this  process  a  lean  gas  would  re- 
sult, as  there  would  be  no  hydrogen,  and  the  proportion  of  ni- 
trogen (inert  gas)  would  be  increased.  Aside  from  this,  ex- 
cessively high  temperatures  would  result  in  the  generator,  pro- 
ducing clinkers  and  other  objectionable  results.  This  is 
avoided  by  the  use  of  a  quantity  of  steam  which  is  carried  in 
by  the  air  and  increases  the  quality  of  the  gas  by  the  addition 
of  hydrogen,  at  the  same  time  lowering  the  temperature  in  the 

The  hot  gas  leaving  the  generator  passes  slowly  downward 
through  the  inner  chamber  of  the  economizer,  around  which  is 
an  annular  space  up  which  air  for  supporting  combustion 
in  the  generator  passes.  The  air,  passing  upward,  ab- 
sorbs the  heat  from  the  inner  chamber  and  is  conveyed  from 
the  upper  part  of  the  economizer  underneath  the  grate  by  means 
of  the  pipe  shown  in  the  illustration.  In  this  way  the  energy, 
which  passes  off  in  the  form  of  sensible  heat  in  the  gas  leaving 
the  generator,  is  utilized  and  increases  the  efficiency  of  the  gas 
making  process. 

The  supply  of  air  to  the  generator  and  the  flow  of  gas 
through  the  plant  is  produced  by  the  suction  of  a  positive  ro- 
tary exhauster  connected  to  the  scrubber.  The  exhauster,  nor- 
mally, places  the  gas  plant  under  suction  so  that  when  the 
pokeholes  in  top  of  generator  are  open  there  will  be  an 
inflow  of  air.  To  offset  this  suction,  a  positive  supply 
of  steam  is  used  for  saturating  the  air  for  generator. 
Steam  is  introduced  by  means  of  a  steam  blower  such 
as  is  frequently  used  for  forcing  draft  under  boilers; 
by  means  of  this  device  the  suction,  caused  by  the  exhauster, 
is  neutralized  and  atmospheric  pressure  can  be  maintained  in 
the  top  of  generator  at  all  times.  This  is  of  great  advantage, 
for  the  reason  that  attention  may  be  given  to  the  fires  without 
inflow  of  air  or  outflow  of  gas. 

Soot,  tar,  and  other  impurities  are  removed  from  the  gas 
in  the  scrubber,  which  consists  of  a  steel  cylindrical  tank,  high 
in  proportion  to  its  diameter.  A  coke  column,  supported  by 
trays,  extends  to  within  about  5  feet  of  the  top.  Above  the 
upper  surface  of  the  coke  are  located  water  sprinklers,  and 
over  the  sprinklers  between  two  trays  is  a  layer  of  excelsior. 
The  gas,  passing  upward  through  the  coke,  intimately  mixes 
with  the  water  flowing  downward;  thus,  the  tarry  particles 
adhere  to  the  rough  surfaces  of  the  coke  and  are  carried  away 

Vol.  Ill,  No.  2]   ANTHRACITE  PRODUCER  GAS  :  FLINN 


by  the  water.  The  water  mechanically  mixed  with  the  gas  is 
removed  by  the  excelsior.  Between  the  economizer  and  scrub- 
ber is  a  3-way  water  sealed  valve,  so  designed  that  it  is  impos- 
sible for  both  the  vent  to  atmosphere  and  the  inlet  to  scrubber 
to  be  open  at  the  same  time.  Tbe  valve,  being  water  sealed  in 
both  positions,  insure  tightness. 

The  gas  is  drawn  from  the  plant,  compressed,  and  deliv- 
ered to  the  gas  mains  by  means  of  a  positive  rotary  exhauster. 





Fig.   6.      General   View   of   Large   Water   Sealed   Producer   Gas   Plant    Supplying 

Gas  to  Cold  Rolled  Steel  Annealing  Furnaces,  Sherardizing  Kilns 

and   Japanning   Ovens. 

Several  methods  are  employed  to  maintain  a  constant  pressure 
in  the  gas  mains,  the  usual  manner  being,  where  steam  is  avail- 
able, to  drive  the  exhauster  by  a  steam  engine.  A  diaphragm 
pressure  regulator  controls  the  speed  of  the  engine  so  only  that 
amount  of  gas  is  delivered  as  is  required,  the  diaphragm  being 
set  to  maintain  the  desired  pressure  in  the  mains.  When  a 
motor  is  used,  there  is  a  pipe  connection  leading  from  the  deliv- 
ery side  back  to  the  suction  side  of  the  exhauster.  In  this  pipe 
connection  is  placed  a  back  pressure  valve  which  is  adjusted  to 
open  at  the  pressure  to  be  carried  in  the  gas  mains.     The  speed 



[May.  1011 

of  the  exhauster  is  usually  constant  and  equal  to  the  maximum 
demands.  By  this  arrangement  there  is  always  circulating 
about  the  exhauster  through  the  relief  valve  a  quantity  of  gas. 
A  drawback  to  this  method  is  that  the  power  required  to  drive 
the  exhauster  is  excessive.  In  the  larger  installations  a  varia- 
ble speed  motor  is  frequently  used  so  that  the  attendant  to  the 
plant  can  keep  the  speed  of  exhauster,  within  reasonable  limits, 
proportional  to  the  load. 

BT        -  1 

B       1     '         1 





Exhauster  Equipment  of  a  Large  Producer  Gas  Plant. 

In  plants  of  large  capacity  a  water  sealed  generator  is  used 
instead  of  the  shaking  grate  type.  It  differs  only  in  the  man- 
ner of  supporting  the  fuel  column  to  the  extent  that  the  shak 
ing  grate  is  dispensed  with  and  the  air  and  steam  delivered  to 
the  fuel  column  by  means  of  a  tuyere.  The  object  of  this  form 
of  generator  is  to  provide  facilities  for  cleaning  and  removal  of 
ash,  for,  in  large  diameters  the  shaking  grate  becomes  too  cum- 

City  gas  is  the  most  generally  used  gas  fuel,  and  has  a  heat- 
ing value  of  about  600  B.  T.  U.  per  cu.  ft.    Pea  and  No.  1  Buck- 

Vol.  Ill,  No.  2]   ANTHRACITE  PRODUCER  GAS  :  FLINN  225 

wheat  anthracite  coal  contain  12,500  B.  T.  IT.  per  pound.  In 
a  producer  gas  plant  about  80%  of  the  energy  in  the  coal  is 
made  available  in  the  gas,  so  that  for  every  pound  of  coal  gasi- 
fied there  are  10,000  B.  T.  U.  delivered  into  the  gas.  Theoret- 
ically, then,  60  pounds  of  coal  burned  in  the  producer  plant  will 
generate  the  equivalent  of  1,000  cu.  ft.  city  gas.  Taking  into 
consideration,  stand-by  losses  and  the  relative  efficiencies  in 
combustion  of  city  and  producer  gas,  practice  shows  that  80 
pounds  of  coal  is  a  reasonable  figure  for  heating  operations  up 
to  the  requirements  of  hardening,  tempering  and  annealing. 

As  an  illustration  of  economy  in  use  of  producer  gas:  As- 
sume a  can  making  factory  where  city  gas  lias  been  used  for 
heating  solder  baths,  soldering  irons,  and  the  various  tools  used 
in  this  manufacture,  and  where  the  gas  consumption  has  been 
780  M.  cu.  ft.  per  month  at  $1.00  per  M. ;  an  anthracite  producer 
gas  plant  has  been  installed  and  the  comparative  costs  are: — ■ 
City  Gas. 

780  M.  cu.  ft,  @  $1 .00  = $780.00 

Producer  Gas. 
To   displace   780   M.   cu.   ft.    city    gas   required    62,400 

pounds  or  31.2  tons  of  No.  1  Buckwheat  coal. 
Cost  of  Producer  Gas  per  Month. 

Coal  31 .2  tons,  @  $3.15  = $  08.28 

Water  for  cleaning  eras,   2  gallons   per  pound   of  coal, 

124.800  gallons  @  10c  per  M 12.48 

Power  for  operating  exhauster,   8  IT.   P.,   @  $3.00   per 

month    24.00 

Steam,   Vj  pound   per  1    pound   coal,  or  31,200  pounds, 

requiring  5,200  pounds,  or  2.6  tons  coal  @  $3.15.  .  .        8.19 

Labor,  part  of  one  man's  time,  @  $1.00  per- day 26.00 

Interest,  depreciation,  maintenance,  @  12^%  on  $5,000 

investment   52.08 

Total  cost  producer  gas  per  month $221.03 

This  shows  a  saving  over  city  gas,  therefore,  approximating 
$559.00  per  month,  or  $6,708.0*0  per  year;  and  also  that  the 
equivalent  of  1,000  cu.  feet  of  city  gas  is  made  for  about  28.4c. 



The  problems  to  be  met  with  in  the  design  and  develop- 
ment of  the  aeroplane  are  numerous  and  of  widespread  inter- 
est to  technical  men  all  over  the  world  at  the  present  time. 
There  are  thousands  of  experimenters  working  along  the  lines 
of  aeroplane  development  and  a  great  many  ideas  are  being 
tried  out  in  practice.     Now  that  the  possibilities  of  the  aero- 




£L£MTlON . 




Fig.   1. 

plane  have  been  fairly  well  indicated  by  many  successful 
flights,  the  interest  of  the  engineering  profession  is  being 
aroused,  and  a  much  more  logical  development  of  the  numer- 
ous problems  will  be  attained,  together  with  the  consequent 
shortening  of  the  time  required  to  reach  the  practical  stage. 
It  is  with  the  hope  of  creating  some  interest  in  the  aeroplane 
from  the  engineering  point  of  view  that  the  writer  will  present 

''Class   of  1907.     Mechanical    Engineer,   with   Mr.   Harold   F.   McCormick,    Har- 
vester  Bldg.,   Chicago. 

Vol.  Ill,  No.  2] 



the  following  general  consideration  of  the  more  salient  fea- 
tures of  the  problem  of  powering  an  aeroplane. 

We  shall  select,  for  the  sake  of  simplicity,  an  aeroplane  of 
the  monoplane  type  such  as  the  Bleriot  machine  and  let  Fig.  1 
represent  a  plan  and  side  elevation  of  it  as  running  horizon- 
tally in  the  direction  of  the  arrow.  Referring  to  the  figure, 
"a"  represents  the  main  supporting  surface,  "b"  the  tail  sur- 
face, "c"  the  rudder,  "d"  the  propeller  (which  in  this  ma- 
chine is  a  tractor,  since  it  draws  the  aeroplane  along),  and 
"e"  the   wheel   for    running    along    the    ground    before  the 





Fig.   2.  Fig.   3. 

speed  necessary  to  sustain  the  machine  is  attained.  In  order 
to  study  the  forces  acting  on  the  aeroplane,  let  Fig.  2  represent 
the  side  view  of  the  main  surface,  with  '  O  '  the  center  of 
gravity  of  the  machine.  There  will  be  three  forces  acting 
when  in  horizontal  flight ;  ON  the  resultant  reaction  of  the 
air  pressure  on  the  entire  machine;  OW  the  weight,  acting,  of 
course,  vertically  downward ;  and  OP  the  pulling  force  exerted 
by  the  propeller.  For  the  purpose  of  this  discussion,  the  above 
forces  are  considered  as  concurrent.  This  is  practically  true 
for  most  successful  aeroplanes. 

In  flight  at  a  uniform  speed,  the  system  of  forces  is  in 
equilibrium  and  it  is  convenient  to  replace  ON  by  its  compo- 
nents perpendicular  to  and  parallel  to  the  line  of  motion.   This 

228  THE  ARMOUR  ENGINEER  [May,  1911 

is  shown  in  Fig.  3  where  OL  is  the  component  perpendicular  to 
the  line  of  flight,  and  OR  is  one  parallel  to  the  line  of  flight. 
The  forces  acting  may  be  considered  to  be,  then,  the  propeller 
force  OP,  the  weight  OW,  the  "lift"  OL  and  the  resistance  to 
motion  OR. 

The  force  OR  is  opposed  to  forward  motion  and  must 
therefore  be  balanced  by  OP.  The  lift  OL  must  be  balanced 
by  OW,  the  weight  of  the  entire  outfit,  including  operator, 
fuel,  etc.  As  a  basis  for  supplying  the  proper  amount  of  pow- 
er, the  value  oFt-he  propelling  force  must  be  determined.  We 
know  it  must  be  equal  OR,  hence  the  value  of  OR  must  be  de- 
termined. The  most  logical  way  to  do  this  at  the  present  time 
is  to  make  as  close  an  estimate  as  possible  of  the  resistance  of 
each  part  of  the  machine,  including  the  horizontal  components 
of  the  air  pressures  on  its  surfaces.  This  may  be  done  with  a 
fair  degree  of  approximation  for  any  of  the  well  known  types, 
but  the  value  thus  obtained  must  be  checked  by  comparison 
with  values  deduced  from  observations  on  real  machines  in 
actual  flight. 

Experiments  have  been  made  with  an  aeroplane  having  its 
propeller  so  mounted  in  the  bearings  that  a  calibrated  spring 
would  indicate  the  actual  thrust  during  flight.  The  results 
obtained  under  various  conditions  with  this  kind  of  apparatus 
give  us  valuable  data  for  future  calculations. 

There  are  other  ways  of  finding  the  resistance  by  observa- 
tion of  machines,  and  the  most  obvious  is  to  allow  the  aero- 
plane to  glide  with  the  engine  shut  off.  Under  these  condi- 
tions the  path  of  flight  is  no  longer  horizontal,  for  the  machine 
approaches  the  earth  at  a  small  angle  to  the  horizontal.  In 
Pig.  4  this  state  of  affairs  is  shown.  The  path  of  flight  makes 
the  angle  6  with  the  horizontal  and  the  size  of  this  angle  is 
determined  by  the  resistance  as  compared  with  the  weight  of 
the  aeroplane.  This  is  true  because  the  propelling  force  OR' 
must  be  component  of  the  weight  in  the  direction  of  motion 
and  the  machine  will  adjust  itself  at  such  an  angle  that  this 
force  exactly  equals  the  resistance  OR.  The  component  of  the 
weight  OW'  perpendicular  to  the  line  of  flight  balances  the 
lifting  force  OL  and  the  aeroplane  glides  at  a  uniform  velocity 
at  an  angle  6  with  the  horizontal. 

Now  the  angle  WOW'  is  also  equal  to  6,  and  WW'-^-WO 
equals  sine  0.  But  WW'=R'0,  hence  R'0-=-WO  equals  sine 
6.  Therefore  if  we  measure  the  gliding  angle  and  know  the 
total  weight  of  any  given  machine,  the  resistance  in  the  line  of 
flight  becomes  a  matter  of  calculation  and  is  equal  to  WO 
sine  0. 

Vol.  Ill,  No.  2]  AEROPLANE  POWER:      JAMES 


It  is  clear,  after  the  above  condition  is  realized,  that  in 
order  to  have  horizontal  flight  under  power,  the  propeller  must 
supply  a  force  equal  to  this  resistance.  An  expression  showing 
the  relation  between  the  thrust  and  the  engine  power  will  be 
necessary,  therefore,  to  find  the  power.  The  Thrust  Horse 
Power  may  be  expressed  by  the  equation : 

T.H.P.  = 

where  T  =  thrust  or  pull  of  propeller  in  pounds,  V  =  velocity 

Fig.    4. 

of  flight  in  feet  per  second,  and  550  converts  the  foot  pounds  of 
work  per  second  of  the  numerator  into  horse  power. 

If  the  efficiency  of  propulsion  be  represented  by  e,  then 
the  Brake  Horse  Power  of  the  engine  itself  will  be 


B.H.P  = 


By  examining  the  above  equation,  we  see  that  everything  else 
remaining  constant,  the  B.H.P.  varies  directly  as  the  thrust 
required,  or  in  other  words,  if  we  have  the  power  required  to 
develop  say  100  pounds  thrust  at  the  propeller  at  any  given 
speed  of  translation  through  the  air,  we  know  that  if  a  200 



[May,  1911 

pound  thrust  is  required  thp  power  must  be  doubled.  Hence, 
if  we  work  out  our  data  on  the  basis  of  100  pounds  thrust,  we 
simply  have3  to  multiply  the  value  for  the  power  obtained  from 
these  figures  by  the  ratio  of  the  required  thrust  to  100  pounds. 
Substituting  in  the  formula  above  the  value  100  pounds 
for  T  we  have 

B.H.P  = , 

hence  for  any  given  value  of  "V"  a  curve  may  be  plotted  with 
B.H.P.  as  abscissa,  and  efficiency  "e"  as  ordinate.  This  has 
been  done  for  a  series  of  values  of  V  ranging  from  20  to  75 
miles  per  hour,  in  steps  of  5  miles,  and  the  diagram  shown  in 
Fig.  5  drawn.  This  covers  a  range  of  propeller  efficiency  from 
35%  to  80%  thereby  including  all  present  practice. 


%r.ustm,  4./.T.  iso7. 

'"  brake:    horse   power  or  engine 


To  illustrate  the  use  of  the  above  in  figuring  out  the 
amount  of  power,  let  us  take  the  case  of  a  Wright  aeroplane 
having  the  following  characteristics:  Normal  speed  35  miles 
per  hour  or  51.3  feet  per  sec,  gliding  angle  8°,  total  weight 
about  1100  pounds.  The  thrust  necessary  for  horizontal  flight 
would  be  T  =  1100  sin  8°  =  1100X0.139'=  153  pounds.  There- 
fore, assuming  60%  efficiency 

B.H.P.  = =  23.75 

This  result  can  be  found  by  using  the  chart  reading  15.5  B.H.P, 

Vol.  Ill,  No.  2]  AEROPLANE  POWER :     JAMES  231 

at  the  intersection  of  the  35-mile  line  with  the  60%  efficiency 
line  and  multiplying  it  by  the  ratio  of  153  to  100  or  15.5X1-53 
=  23.7  B.H.P. 

The  Wright  engine  has  a  full  load  capacity  of  30  to  32 
horse  power,  thus  having  a  reserve  power  of  about  25%  which 
is  called  into  play  when  ascending  from  the  ground,  or  oppos- 
ing a  head  wind. 

A  Bleriot  XI  machine,  such  as  we  used  in  Fig.  1  for  exam- 
ple, has  the  following  characteristics:  Total  weight  770 
pounds,  normal  speed  50  miles  per  hour,  or  73.34  feet  per  sec- 
ond, gliding  slope  of  about  1  in  7.5,  efficiency  of  propulsion 


50%.     Hence    the   thrust  required   will   be   T  = or  102.6 

pounds,  and  the 


B.H.P.  = =  27.35 

This  result  may  also  be  obtained  from  the  chart  by  reading 
26.7  B.H.P.  at  50%  efficiency  and  50  miles  per  hour,  then  multi- 
plying by  102.6-^100  or  1.026X26.7  =  27.4  B.H.P.  as  above. 
The  Bleriot  XI  is  furnished  with  a  gnome  motor  which  devel- 
ops about  45  actual  brake  horse  power,  hence  there  is  a  reserve 
of  about  40%. 

The  chart  is  useful  in  getting  a  rapid  survey  of  the  power 
problem,  showing  how  much  power  will  be  necessary  for  hori- 
zontal flight,  as  it  enables  a  person  to  pick  out  the  value  for 
any  probable  or  desired  set  of  conditions  as  to  speed,  efficiency 
and  thrust  or  resistance.  It  also  shows  in  a  graphical  way  the 
value  of  high  efficiency  and  the  penalty  for  low  efficiency  of 


By   E.   J.   HEINEN,   M.    E.* 

In  the  design  of  a  central  station  a  broad  scientific  train- 
ing, extensive  experience  and  technical  ability  are  required. 
Knowledge  of  the  mechanical,  electrical  or  civil  subjects  will 
not  alone  suffice,  although  all  of  these  are  called  into  play  in 
the  design  of  a  successful  central  station.  Soon  after  the  intro- 
duction of  alternating  current  machinery  and  long  distance 
transmission  lines,  the  three-phase  induction  motor  secured 
a  place  in  manufacturing  industries  which  has  brought 
about  a  standardization  of  power  plant  machinery,  the  results 
of  which  are  noticeable  in  some  of  the  larger  plants  of  late 

Tn  the  planning  and  designing  of  a  power  plant  the  pre- 
liminary is  of  the  greatest  importance,  and  many  factors  that 
affect  the  general  results  cannot  be  decided  upon  except 
through  available  data  and  much  study — guided  by  past  expe- 
rience. The  first  step  is  the  determination  of  the  load  curve 
which,  in  case  there  is  no  available  data,  involves  a  thorough 
study  of  local  conditions.  These  load  curves,  with  careful 
study  of  overload  and  reserve  power,  determine  the  capacity  of 
the  plant  and  proper  size  of  units.  The  layout  and  arrange- 
ment of  these  largely  depends  upon  the  type  of  apparatus  se- 
lected— the  prime  movers,  generators,  boilers,  and  auxiliary 
machinery.  Unit  system  is  very  much  to  be  favored  in  a  de- 
sign, because  of  its  many  advantages  and  few  disadvantages, 
and  consisting  as  it  does  of  a  number  of  separate  plants  of  uni- 
form equipment  side  by  side.  The  piping  in  a  unit  system  of 
installations  usually  cross  connect  all  the  units,  thus  permit- 
ting any  one  unit  to  be  operated  with  boilers  normally  as- 
signed to  their  own  unit 

The  condensing  system  is  usually  of  the  independent  type, 
although  the  use  of  this  system  is  not  always  the  best  policy, 
for  when  large  units  are  installed,  and  there  are  not  too  many 
joints  and  long  runs  of  pipe,  the  interchangeable  system  may 
prove  the  more  profitable.  The  endeavor  to  place  the  con- 
denser close  to  the  low  pressure  end  of  the  prime  mover,  with 
no  means  provided  for  an  atmospheric  exhaust,  makes  it  nec- 
essary to  shut  down  the  unit  whenever  repairs  on  the  con- 
denser are  necessary. 

The  arrangement  of  the  machinery  should  be  such  as  to 
permit  access  for  repairs;  the  passage  ways  should  be  ample 

♦Class    of    1904.      Chief    Estimator,    Mechanical    Department,    Minneapolis    Steel 
and  Machinery  Co.,  Minneapolis,  Minn. 

Vol.  Ill,  No.  2]  POWER  PLANTS :      HEINEN  233 

to  allow  for  parts  of  a  machine  to  be  placed  out  on  the  floor, 
which,  in  turn,  should  be  designed  to  carry  any  load  as  may 
occur  in  such  cases.  The  various  machines  should  be  so  placed 
that  the  pipe  lines  will  be  short,  and,  wherever  possible,  bends 
should  be  provided  to  allow  for  expansion.  Tf  the  dimensions 
of  the  site  are  fixed  by  circumstances,  it  may  not  be  possible 
to  obtain  the  most  de'sirable  arrangement  of  the  equipment. 
The  different  advantages  and  disadvantages  can  best  be  de- 
termined by  considering  a  number  of  alternative  arrangements, 
consisting  of  various  types  of  apparatus  together  with  the 
layout  of  necessary  piping.  The  final  arrangement  can  only 
be  decided  upon  after  careful  study  and  results  of  past 

The  location  of  a  power  plant  is  often  difficult  to  deter- 
mine. It  properly  depends  upon  the  source  of  power  to  be  de- 
veloped, but  is  often  governed,  in  the  case  of  a  gas  or  steam 
plant,  by  conditions  such  as  fuel,  water,  labor  supply  and  dis- 
posal of  waste.  Tf  a  water  power  plant,  the  location  must  be 
accessible  for  building  material  and  machinery,  and  yet  located 
at  a  point  to  obtain  the  maximum  hydraulic  head. 

Owing  to  the  possibility  of  pipine  water  from  a  distance, 
the  water  problem  of  a  nlant  is  considerably  reduced.  With 
such  a  snpplv  it  is  advisable  to  provide  storage  tanks,  or  a  res- 
ervoir close  to  the  plant,  to  guard  against  interruptions  such 
as  a  shut-off  for  repairs.  Tf  city  water  is  the  supply  to  a  plant. 
it  is  a  good  plan  to  provide  a  tower  tank  for  emergency  cases. 
Such  a  lavout  has  shown  the  possibility  of  operating  a  plant 
after  the  bursting  of  a  city  main  and  until  repairs  on  same 
could  be  made.  Tf  the  water  must  be  purchased,  it  is  advisable 
to  develop  its  own  supply.  The  nnantity  of  water  required 
depends  upon  whether  surface  or  jet  condensers  are  used:  m 
the  case  of  surface  condensers,  the  water  condensation  may  be 
used  for  boiler  feed.  Tt  is  almost  imnossible  to  obtain  good 
water  for  boiler  feeding  and  consequently  the  boilers  renuire 
constant  attention  and  most  be  cleaned  at  regular  intervals.  _ 
The  modern  method  of  dealing:  with  feed  water  of  this  kind  is 
to  remove  the  scale  forming  substances  before  they  reach  the 
boiler.  The  installations  of  water  softening  plants  for  purify- 
in^  boiler  feed  water  are  becoming  more  numerous  and  have 
proven  their  efficiency  by  reducing  fuel  consumption,  expense 
of  boiler  cleaning  and   repairs. 

The  fuel  snpplv  and  the  question  of  handling  the  same  is 
of  the  greatest  importance,  for  the  cost  of  fuel  must  include  the 
expense  of  handling  it  between  the  cars  and  grates,  and  the  dis- 

234  THE  ARMOUR  ENGINEER  [May.  11)11 

posal  of  ashes.  The  expense  of  handling  coal  is  reduced  to 
a  minimum  by  delivering  it  directly  to  the  plant  in  cars 
or  barges,  and  carting  the  ashes  to  a  dump,  since  the  coal  re- 
quired is  about  fifteen  times  the  weight  of  the  ashes.  With  in- 
crease in  size  of  plants,  the  importance  of,  a  reserve  supply  of 
coal  to  guard  against  interruption  of  service  becomes  evident. 
Water  transportation  is  closed  in  many  localities  for  several 
months  in  the  year,  and  railroads  are  subject  to  interruptions 
through  wrecks,  strikes  or  badly  congested  freight  which  make 
it  impossible  to  tell  how  long  a  train  will  be  on  the  road. 

In  localities  where  natural  gas  is  available  for  fuel  under 
boilers  or  in  gas  engines,  a  reserve  is  very  seldom  kept,  but 
duplicate  pipe  lines  are  installed  to  insure  against  an  interrup- 
tion of  service.  Fuel  oil  has  been  used  to  advantage,  being  de- 
livered to  the  plant  by  pipe  lines,  cars  or  boat.  A  storage  tank 
provides  for  a  supply  between  shipments,  or  any  interruptions 
that  may  occur  due  to  weather  conditions  and  other  causes. 
The  fuel-storage  plant  should  be  located  near  the  plant,  if  suf- 
ficient ground  space  is  available.  A  fuel-storage  plant  such  as 
bunker  capacity  over  the  boilers  involves  considerable  invest- 
ment in  its  equipment  and  maintenance,  but  is  an  insurance 
against  interruption  in  fuel  supply  in  case  of  a  conveyor 
break  down. 

The  design  of  the  building  and  arrangement  of  the  machin- 
ery often  destroys  the  architectural  features  by  the  attempt  to 
place  the  coal  handling  plant  in  the  most  conspicuous  point  in 
the  layout,  and  thus  possibly  save  a  few  dollars.  This  fact  in 
some  instances  interferes  to  such  an  extent  that  it  appears  as 
if  there  was  a  coal  handling  plant  with  a  power  plant  annex. 
It  is  often  possible  to  desiern  the  coal  handling  plant  to  har- 
monize with  the  main  building  with  but  slight  additional  cost; 
however,  this  is  usually  offset  by  a  reduction  in  the  up-keep 
on  the  structure  and  equipment. 

The  layout  of  the  plant  and  the  types  of  apparatus  selected 
for  the  generation  of  steam  and  electricity  usually  determine 
the  design  of  the  main  building  and  the  steel  framing.  The  unit 
system  of  design  for  the  mechanical  installation  permits  the 
same  system  to  be  used  in  the  design  of  the  steel  superstructure. 
In  power  plant  design,  however,  it  is  the  results  attained  from 
the  complete  machine  which  must  be  considered,  and  while  a 
good  architectural  effect  is  to  be  desired,  the  efficiency  of  the 
plant  cannot  be  sacrificed  to  gain  it.  For  the  interior  finish  of 
the  walls,  a  light  blue-colored  pressed  brick  and  an  enam- 
eled tile  wainscot  four  cr  six  feet  in  height  above  the  floor  has 

Vol.  Ill,  No.  2]  POWER  PLANTS :     HEINEN  235 

many  advantages,  since  such  a  finish  never  requires  renewal, 
and  is  easv  to  keep  clean. 

The  cheapest  form  of  illumination  is  obtained  by  large 
windows,  large  both  in  height  and  in  width.  Where  exposed 
at  any  time  to  the  direct  rays  of  the  sun,  rough  surface  or  trans- 
lucent glass  may  be  used,  or  wire  glass,  owing  to  its  advantages 
as  a  fire  retardent.  Skylights  furnish  a  very  desirable  means 
of  supplving  light,  particularly  for  the  operating  floor.  These 
may  be  iocated  in  every  other  bay,  or  the  entire  length  of  the 
bay,  and  can  be  glazed.  For  the  purposes  of  ventilation  a  mom- 
tor  is  usually  provided  over  both  the  operating  and  boiler 
rooms.  In  the  operating  room  glazed  sashes,  opening  on  pivots, 
are  usually  provided.  The  monitor  over  the  boiler  room  that 
houses  the  machinery  for  distributing  the  coal  has  glazed  sashes 
on  pivots  in  order  to  provide  for  illumination. 

Roofing  on  some  prominent  plants  consists  of  Spanish  roll 
tile  set  on  brook  tile  carried  by  T-irons  and  supported  by  the 
purlins.  Reinforced  concrete  slabs  are  just  as  efficient  as  the 
brook  tile,  and  with  this  construction  a  coat  of  mortar  is  not 
required  on  the  lower  surface  to  secure  a  uniform  finish. 

Platforms  and  walkways  are  often  confined  to  fixed  limits, 
and  these  should  be  considered  in  the  general  layout  so  as  to 
avoid  insufficient  clearance  and  necessity  of  walking  on  pipes 
in  order  to  reach  valves.  Gratings  constructed  of  light  ma- 
terial between  channel  iron  stringers  form  a  curb  to  prevent 
tools  being  kicked  overboard  accidentally,  for  a  tool  disap- 
pearing over  the  edge  at  an  inopportune  time  or  place  may 
cause  serious  damage. 

Concrete  slabs  and  arches  for  flooring  have  replaced  the 
porous  or  hard-clay  hollow  tile.  The  floor  finish  can  be  colored 
by  mixing  in  lamp  black  so  that  oil  drippings  will  not  be  so  con- 
spicuous ;  a  hard  finished  surface  of  this  kind  is  also  a  preven- 
tion of  dust— a  verv  desirable  feature  in  operating  rooms.  The 
sanitarv  curve  should  be  used  at  all  corners,  and  all  pipes  pass- 
ing through  the  floor  should  be  surrounded  by  suitable  thimbles 
with  about  four  inches  clearance  above  floor  level  to  protect 
the  pipe  covering  from  wash  water.  Drainage  slopes  should 
also  be  arranged  with  floor  drains,  so  that  as  far  as  possible 
water  will  run  off. 

Alain  passagewavs  should  be  of  ample  width  and  should 
not  be  less  than  five  feet.  Stairs  should  be  as  straight  as  pos- 
sible in  order  to  carrv  pipes  or  other  long  pieces  from  place  to 
place  In  places  where  space  is  limited,  ladders  may  be  used 
to  advantage;  however,  stairs  of  steep  incline  with  treads  ot 
special  construction  are  often  used  to  advantage. 

230  THE  ARMOUR  ENGINEER  [May,  1911 

Main  doorways  to  the  boiler  and  operating  room  should  he 
of  sufficient  size  to  permit  running  railroad  cars  into  the  build- 
ing where  they  may  be  unloaded  by  the  crane. 

The  foundation  is  the  most  important  portion  of  the  power 
plant,  and  where  rock  or  other  solid  bottom  can  be  reached  in 
a  reasonable  distance,  the  foundation  should  be  carried  down 
to  it.  In  most  cases  when  the  plant  is  located  on  made  or  filled 
land,  isolated  piers  are  liable  to  unequal  settlement;  in  addition, 
there  is  always  the  uncertainty  in  regard  to  future  development 
which  may  make  necessary  radical  changes  in  the  distribution 
of  the  loads.  For  this  reason  the  mat  foundation  which  insures 
equal  settlement  and  at  the  same  time  permits  any  desired 
shifting  of  the  loads  is  the  one  most  suitable  for  a  power  plant. 
In  this  latter  method  the  area  of  the  site  is  filled  with  piles  at 
practically  uniform  spacing,  and  these  capped  with  a  mono- 
lithic mass  of  concrete. 

The  erection  of  a  central  station  or  a  power  plant  is  a 
branch  quite  different  from  the  design.  The  engineer  in  charge 
of  the  design  must  possess  knowledge  of  how  certain  machines 
are  assembled  and  how  the  various  parts  of  a  machine  are 
handled  during  the  process  of  erection.  This  knowledge  will 
enable  him  to  allow  for  proper  size  openings  in  walls  through 
which  various  parts  must  be  taken.  He  must  also  know  where 
to  allow  for  his  last  piece  of  pipe  to  complete  the  pipe  lines. 
These  are  but  a  few  examples  of  many  that  an  engineer  will 
find  himself  up  against  during  the  design  of  a  complete  plant. 

After  the  plans  are  complete  in  that  all  the  machinery  is 
permanently  placed  and  all  the  pipe  lines,  valves,  fittings,  etc., 
are  located,  they  must  be  carefully  checked  and  dimensioned. 
In  checking  the  various  pipe  lines  it  is  not  only  necsesary  to 
check  the  dimensions,  but  lines  must  be  carefully  checked  to  see 
that  ample  provision  has  been  made  for  supporting  them,  and 
that  proper  allowance  has  been  made  for  expansion.  In  the 
pipe  layout  it  is  of  the  utmost  importance  to  constantly  bear  in 
mind  the  flexibility  of  the  plant  in  case  of  a  breakdown  of  a 
certain  unit  or  any  part  thereof. 

The  next  in  order  is  to  make  out  a  list  of  the  material 
necessary  for  the  complete  piping  system.  While  this  may 
seem  at  first  sight  to  be  a  tedious  job,  it  can  best  be  accom- 
plished by  first  securing  a  comprehensive  idea  of  what  is  re- 
quired, and  then  by  keeping  in  mind  what"  purpose  the  bill  of 
material  is  to  serve.  If  it  is  merely  to  serve  as  a  bill  of  mate- 
rial from  which  to  make  up  the  various  pieces  in  the  shop,  or  if 
it  is  to  serve  as  a  guide  for  the  men  on  the  erection,  will  deter- 
mine how  it  shall  be  made  up.  Often  it  is  necessary  that  it 
serve  for  both  the  men  in  the  shop  and  the  men  in  the  field, 

Vol.  Ill,  No.  2]  POWER  PLANTS  :     HEINEN 

A  sj^stem  not  altogether  new  but  which  has  given  perfect 
satisfaction  where  used  on  a  number  of  jobs  to  the  writer's 
knowledge,  is  given  herewith.  The  various  pipe  lines  are  num- 
bered in  such  a  manner  that  each  piece  as  made  up  in  the  shop 
bears  a  number.  This  number  is  placed  inside  a  heavy  circle 
placed  tangent  to  the  side  of  the  pipe  fitting  or  valve,  as  the 
case  may  seem  best.  These  numbers  have  a  letter  prefix  which 
indicates  whether  the  particular  piece  of  pipe  is  a  steam,  ex- 
haust, or  water  pipe.  Such  pipes  are  marked  with  respective 
prefixes  and  numbers,  as  S  20,  E  14,  or  W  33.  On  the  bill  of 
material  these  marks  are  placed  with  the  particular  piece  under 
the  proper  list  and  in  such  a  manner  that  all  steam  pipes,  valyes 
and  fittings  are  listed  together,  likewise  all  exhaust  pipes  and 
fittings.  Where  this  has  been  done  all  of  the  various  lines  are 
made  up  in  groups.  By  numbering  each  piece  consecutively 
this  system  can  be  made  up  in  such  a  way  that  by  means  of  an 
index  in  connection  with  the  bill  of  material  one  can  easily  find 
the  item  number  for  any  particular  piece  in  any  particular  pipe 
line.  These  marks  are  printed  on  the  various  pieces,  after  they 
have  been  tested  and  before  leaving  the  shop,  in  white  paint. 
Thus  one  is  able  to  locate  a  piece  of  pipe  or  fitting  on  the  plans. 
By  referring  to  the  index  we  obtain  the  page  numbers  with 
item  numbers,  and  finally  the  mark  that  the  particular  piece  of 
pipe  will  bear.  Likewise  upon  looking  at  a  piece  of  pipe  and 
noting  the  mark,  one  is  able  to  tell  at  an  instant  whether  the 
piece  in  question  is  a  steam,  exhaust  or  some  other  pipe.  Then 
again  by  following  a  route  in  affixing  these  numbers  to  the  pipes 
the  system  becomes  more  valuable  both  in  locating  material  and 
also  as  a  guide  in  referring  the  home  office  to  the  pipe  or  fitting 
that  is  in  question.  Furthermore,  it  serves  as  a  protection  in 
placing  the  fitting  where  it  is  intended  to  go. 

This  system  has  been  worked  out  so  thoroughly  that  it  was 
possible  to  ship  complete  material  for  a  central  station  from  a 
most  northerly  point  of  the  U.  S.  to  Mexico,  and  there  erect  a 
complete  plant  with  but  two  or  three  very  light  shipments  dur- 
ing its  construction.  This  particular  plant  consisted  of  six  B.  & 
W.  boilers  set  in  three  batteries,  four  cross  compound  condens- 
ing engines  directly  connected  to  alternators,  independent  jet 
condensers,  low  service  pumps  and  boiler  feed  pumps,  feed 
water  heater,  and  the  necessary  pipe  to  complete  the  plant  for 


By  E.  E.  MAHER.* 

In  the  transfer  of  a  solid  into  a  liquid,  or  a  liquid  into  a 
vapor,  a  certain  amount  of  heat  is  required  to  accomplish  the 
transformation.  The  heat  employed  in  making  these  changes 
becomes  latent  and  the  quantity  of  heat  so  employed  must  he 
removed  in  active  form  before  the  transformation  is  accom- 
plished. It  is  upon  this  physical  law  that  the  science  of  refrig- 
eration is  based. 

The  transfer  of.  heat  from  one  body  to  another,  or  the  law 
of  thermodynamics,  must  be  understood  in  the  study  of  this 
subject,  as  it  is  by  the  application  of  this  law  that  we  are  able 
to  accomplish  by  mechanical  means  the  refrigerating  effect 
necessary  to  the  production  of  cold,  which  is  the  absence  of 

The  demands  of  civilization,  whenever  they  become  suffi- 
ciently insistent  or  essential  to  our  further  development,  are 
always  met  by  corresponding  advances  in  science.  It  has 
always  been  so  and  will  continue,  until  we  have  forced  from 
Nature  her  last,  most  deeply  hidden  secret. 

In  the  development  of  the  science  of  refrigeration,  we  have 
progressed  slowly,  and  while  we  have  accomplished  much,  Ave 
are  still  far  from  having  reached  that  point  of  achievement 
which  justifies  any  great  degree  of  complacency.  We  may 
reasonably  expect  future  accomplishment  to  show  our  present 
methods  to  be  crude,  indirect  and  extravagant  to  a  degree. 
This  particular  branch  of  engineering  undoubtedly  offers  an 
attractive  field  for  endeavor.  For  the  ambitious  who  are  pre- 
pared and  willing  to  accept  Nature's  challenge  and  make  the 
sacrifice  which  she  requires  always  as  the  price  of  success,  the 
prize  is  waiting. 

The  ancients  in  warm  climates  cooled  their  drinking  water 
by  swinging  it  rapidly  in  the  open  air  in  open  vessels,  or  in 
skins,  which  were  then  used  quite  generally  as  containers. 
In  this  way  a  portion  of  the  heat  was  absorbed  by  the  air, 
causing  a  fairly  rapid  evaporation,  which  resulted  in  reducing 
the  temperature  of  the  water. 

In  Eastern  countries,  even  today,  methods  almost  as  prim- 
itive  are   employed.     In   Northern   India   ice  is   produced   in 

•j-For  the  data  regarding  the  history  and  development  of  mechanical  refrigera- 
tion, the  writer  is  indebted  to  Mr.  Edwin  S.  Shepard,  Consulting  Engineer, 
and  to  "ICE  AND  REFRIGERATION"  for  the  tables  given. 

♦Formerly  of  Class  of  1905.  Secretary,  the  B,  M.  Osbun  Co.,  Mechanical  Equip- 
ment,   Chicago, 

Vol.  Ill,  No.  2]    MECHANICAL  REFRIGERATION  :    5IAHBR  239 

small  vessels  wrapped  in  damp  cloths  and  placed  in  a  position 
where  a  strong  current  of  air  will  strike  it,  thus  causing  rapid 
evaporation,  a  process  in  which  heat  is  absorbed  from  the  water 
with  a  resulting  lowering  in  temperature  sufficiently  to  cause 
thin  crusts  of  ice  to  be  formed. 

Early  in  the  sixteenth  century  an  Italian  chemist  pro- 
duced a  reduction  in  temperature  by  dissolving  saltpetre  in 
water.  This  was  the  first  recorded  successful  assault  by  science 
on  Nature's  thermal  citadel.  A  few  years  later  another  chem- 
ist succeeded  in  developing  still  lower  temperatures  by  the  use 
of  various  combinations  of  chemicals  such  as  nitrate  of  am- 
monia, sulphuric  acid,  muriatic  acid,  etc. 

The  first  successful  application  of  machinery  to  the  pro- 
duction of  cold,  was  by  one  "Vallance"  in  1824.  This  gentle- 
man constructed  an  apparatus  by  which  air  was  circulated  over 
vats  of  sulphuric  acid.  In  this  process  the  acid  absorbed  the 
moisture  from  the  air  and  thereby  caused  it  to  become  highly 
rarified.  The  rarified  air  was  then  circulated  over  pans  con- 
taining water,  during  which  procedure  the  air  absorbed  the 
heat  from  the  water,  reducing  the  temperature  proportionate- 
ly.   By  a  crude  arrangement  the  process  was  made  continuous. 

During  the  period  from  1824  until  about  1870  many  and 
various  attempts  were  made  to  produce  refrigeration  by  me- 
chanical processes.  Many  attempted  to  accomplish  the  desired 
results  by  compressing  air  and  permitting  it  afterward  to 
expand,  but  this  method  was  found  impractical  after  many 
attempts,  on  account  of  the  large  volume  of  air  necessary  to 
be  handled  and  the  difficulty  of  producing  machinery  that 
would  do  this  work  practically. 

About  the  year  1870  a  machine  was  brought  out  in  Ameri- 
ca with  which  cold  Avas  produced  by  the  evaporation  of  ether. 
The  ether  was  vaporized  in  a  series  of  coils  or  in  a  closed  ves- 
sel connected  with  a  pump,  which  on  its  return  stroke  com- 
pressed the  ether  and  discharged  it  into  another  series  of  coils 
submerged  in  water,  which  in3turn  absorbed  from  the  ether  the 
heat  it  had  taken  up  during  the  process  of  vaporization.  This 
resulted  in  the  ether  being  again  liquified  and  made  available 
for  further  use. 

Thus  was  established  the  first  compression  system,  which 
has  since  become  the  recognized  method,  and  the  cycle  of 
operation  then  employed  is  still  the  accepted  principle  of  all 
compression  systems,  and  is  the  most  practical  known  method 
of  transferring  heat  by  mechanical  means. 

240  THE   ARMOUR  ENGINEER  [May,  1911 

Many  and  costly  experiments  have  been  made,  during 
which  many  refrigerating  agents  have  been  tried:  ammonia, 
sulphurous  oxide,  carbonic-  acid,  nitrous  oxide,  cymogene  and 
other  chemical  compounds,  until  by  experiment  it  was  found 
that  ammonia,  when  dehydrated,  adapted  itself  most  readily 
to  the  requirements  on  account  of  its  extremely  volatile  char- 
acteristic and  its  disposition  to  vaporize  at  temperatures  (when 
pure)  as  low  as  — 28  3/16°  Fahr.  at  atmospheric  pressure. 

Ammonia  is  a  combination  of  two  gases:  nitrogen  and 
hydrogen,  and  takes  the  chemical  symbol  NH3.  Pure  am- 
monia is  colorless  and  alkaline,  and  its  latent  heat  is  greater 
than  that  of  any  other  known  agent.  Its  permanence,  its  char- 
acter of  not  being  inflammable  or  explosive,  and  the  readi- 
ness with  which  it  can  be  produced  has  resulted  in  establish- 
ing anhydrous  ammonia  as  the  chosen  refrigerating  agent. 

Compared  with  water,  its  specific  gravity  at  32°  Fahr. 
is  about  0.6364.  One  cubic  foot  of  liquid  ammonia  weighs 
39.73  pounds.  Its  specific  heat  is  0.50836;  its  latent  heat  of 
evaporation  is  approximately  560  B.T.U.  When  fully  evap- 
orated, the  volume  of  one  cubic  foot  of  liquid  becomes  21.017 
cubic  feet. 

From  what  has  been  said,  the  reader  will  understand  that 
in  the  employment  of  anhydrous  ammonia  as  a  refrigerating 
agent,  the  heat  is  absorbed  from  surrounding  substances,  such 
as  air,  water,  etc.,  by  the  ammonia.  In  its  practical  appli- 
cation it  becomes  necessary  to  confine  the  ammonia  so  that 
it  cannot  escape,  in  order  that  it  may  be  used  again,  other- 
wise the  expense  of  mechanical  refrigeration  would  be  pro- 
hibitive. "This  condition  makes  it  necessary  to  employ  closed 
vessels  in  which  the  ammonia  may  be  expanded  or  vaporized 
and  other  closed  vessels  in  which  it  may  be  condensed  or  re- 
liquified  .  For  this  purpose  pipe  coils  are  generally  used,  the 
liquid  ammonia  being  admitted  to  the  evaporating  coil  by  a 
regulating  valve,  and  the  coil  placed  in  the  room  to  be  refrig- 
erated, or  submerged  in  the  liquid  to  be  cooled.  Coming  in 
contact  with  the  warm  surfaces,  the  ammonia  immediately 
commences  to  absorb  heat,  which  causes  it  to  vaporize  and  ex- 
pand in  the  coil.  At  this  point  it  becomes  necessary  to  remove 
the  vapor  from  the  coil,  this  being  done  by  means  of  a  pump, 
which,  like  any  other  pump,  creates  a  vacuum  into  which  the 
vapor  flows  until  it  reaches  the  pump  piston.  Here,  by  a  valve 
arrangement,  it  is  admitted  past  the  piston,  which  upon  its 
return  stroke,  compresses  the  gas  into  a  comparatively  small 
space,  thereby  rapidly  increasing  its  temperature.  In  this 
condition  it  is  discharged  from  the  pump  cylinder  into  another 



coil,  which  is  either  submerged  in  cold  water  or  arranged  so 
that  the  water  will  flow  over  the  outside,  or  so  that  the  water 
in  some  manner  will  come  in  direct  contact  with  the  outside 
of  the  pipe  in  which  the  ammonia  gas  is  held.  Here  the  heat 
of  compression  which  had  previously  been  absorbed  by  the 
ammonia  in  the  process  of  expansion  is  absorbed  by  the  water 
so  that  the  ammonia  again  becomes  liquid,  ready  for  further 

It  will  thus  be  seen  that  in  the  last  analysis,  the  refrigera- 
tion is  accomplished  by  the  water  during  the  process  of  con- 
densing, and  the  importance  of  the  water  supply  becomes  ap- 

Fig.    1.      Motor-Driven    Single    Acting    Refrigerating    Machine. 

parent.  Upon  the  volume  of  water  available  and  its  temper- 
ature, the  whole  practicability  of  a  refrigerating  or  ice  making 
plant  depends. 

Several  different  types  of  pumps  and  coils  have  been  de- 
signed for  circulating  ammonia  gas.  which  on  account  of  its 
extremely  volatile  character  is  difficult  to  confine,  and  so  it  is 
accessary  in  the  building  of  these  pumps  and  coils  to  exercise 
great  care  to  provide  strong,  closely  fitting  parts. 

Among  the  first  to  recognize  the  commercial  possibilities 
of  mechanical  refrigeration  and  to  engage  in  the  manufacture 
of  special  machinery  and  equipment  for  its  production,  was 
David  Boyle,  a  very  practical  machinist  with  an  inventive 
mind,  who,  about  the  year  1870,  designed  and  built  the  first 

242  THE   ARMOUR  ENGINEER  [May,  1911 

practical  commercial  refrigerating  machine;  afterward  estab- 
lishing in  Chicago  what  came  to  be  a  very  large  industry. 

The  Boyle  machine,  or  pump,  was  of  the  vertical  or  upright 
type  with  duplex,  single  acting  cylinders  operated  by  a  recip- 
rocating engine.  These  machines  were  exceptionally  success- 
ful, and  many  of  them  are  in  use  today,  still  performing  splen- 
did service,  which  is  indisputable  evidence  of  the  excellence 
of  their  design  and  construction.  Other  manufacturers  came 
into  existence  with  the  growing  demand  for  refrigerating  ma- 
chines, all  adopting  the  general  principles  and  design  of  the 
Boyle  machine,  that  is:  the  vertical  single  acting  type  with 
duplex  cylinders,  and  for  many  years  this  was  the  only  type 
of  ammonia  pump  in  use.  Later,  however,  with  the  develop- 
ment of  the  spirit  of  commercialism,  there  came  others  who 
sought  to  build  their  fortunes  by  adopting  a  different  desism — 
one  that  would  be  cheaper  to  manufacture;  and  we  now  find 
ourselves  introduced  to  the  horizontal  double  acting  type  of 
pump,  in  which  but  one  cylinder  is  employed,  with  the  com- 
pression at  both  ends.  The  lower  price  made  possible  by  this 
design  attracted  many  purchasers,  and  the  business  flourished. 
The  newer,  cheaper  desism  of  pump  challenged  the  older  on 
the  ground  of  cost  and  won  many  victories  on  this  ground 
alone.  Some  among  the  original  manufacturers  of  vertical 
machines  abandoning  their  ideals,  adopted  the  newer  design, 
hoping  thereby  to  secure  some  financial  gain  for  themselves. 
Others  held  steadfast  to  the  original  and  sought  by  improved 
manufacturing  methods  and  by  a  consistent  regard  for  their 
obligation  to  the  public,  to  maintain  their  position  in  the  trade, 
and  it  is  significant  that  they  have  been  successful — signally 

With  the  advent  of  the  horizontal,  double  acting  machine, 
many  builders  and  manufacturers,  who  were  at  that  time  en- 
gaged in  the  manufacture  of  other  lines  of  machinery,  with 
little  knowledge  of  the  principles  of  engineering  involved, 
and  with  no  adequate  conception  of. the  requirements  of  the 
refrigerating  machine  business,  engaged  in  their  manufacture, 
attracted  by  the  lure  of  gain ;  and  it  came  to  pass  that  there 
were  nearly  as  many  manufacturers  as  purchasers,  which  oc- 
casioned much  strife  (not  all  have  survived). 

Meantime,  new  uses  had  been  found  for  refrigerating 
machinery  and  the  demand  increased,  \and  is  still  increasing, 
until  now  there  is  scarcely  a  department  of  manufacture  or 
production  in  which  refrigerating  machinery  may  not  be  em- 
ployed to  advantage. 

During  the  period  since  the  horizontal  type  of  pump  has 



been  on  the  market,  there  has  been  much  discussion  and  no 
little  controversy  between  these  manufacturers  and  the  manu- 
facturers of  the  single  acting  type  concerning  the  relative 
merit  of  the  two. 

For  a  long  time,  the  engineering  profession  was  con- 
fused by  the  multiplicity  of  conflicting  claims  that  could  not 
be  proven  because  sufficient  time  had  not  elapsed  to  develop 
or  disclose   the  inherent  weakness   of  the   horizontal   double 

Fig.     2.       Engine-Driven    Single     Acting     Refrigerating    Machine. 

acting  pump,  although  its  defects  had  been  determined  the- 
oretically by  those  of  the  profession  who  had  given  the  sub- 
ject intelligent  and  conscientious  study. 

Now,  however,  with  the  aid  of  critical  tests  made  pos- 
sible by  the  application  of  improved  appliances  and  methods 
of  testing,  aided  also  by  a  clearer  understanding  of  the  prin- 
ciples involved  and  their  application,  we  have  had  proven  for 
us  beyond  cpiestion  that  the  original  design — that  of  the  ver- 
tical single  acting  pump,  in  wThich  compression  is  at  one  end 
of  the  cylinder  only,  is  far,  very  far  superior  to  the  horizontal 
double  acting  type, 



[May,  1911 

During  the  past  two  years  one  of  the  large  manufacturers 
of  refrigerating  machinery  has  made  a  series  of  exhaustive 
tests  to  determine  the  relative  efficiency  of  the  two  types  of 
pumps.  These  tests  show  a  greater  clearance  loss  as  well  as  a 
loss  in  power  required  in  the  horizontal  double  acting  ma- 
chine, as  will  be  noted  in  tbe  detailed  record  of  these  tests 
herein  given : 

Series  XXV.     Runs    461    to    479;    12y2"xl8"    single  acting 

machine,  70  R.  P.  M.,  185  lbs.  gauge  condensing  pressure; 

95.5°  F.  Liquid  at  expansion  valve. 



in  Suction 



Pipe  (by 



Temperature            Compressor 



in  '/(  of 


Ton  by 

I.  H.  P. 



displacement       P. 


per  Ton 

5  lbs. 


0  24 




5  lbs. 






5  lbs. 


1 .46 




5  lbs. 






5  lbs. 






16.57  lbs. 






16.57  lbs. 






16.57  lbs. 


1 .46 




16.57  lbs. 






16.57  lbs. 






25  lbs. 






25  lbs. 






25  lbs. 






25  lbs. 






25  lbs. 






Series  XXVI.     Runs  480   to  498.     12y2"xl8"    double    acting 

compressor,  70  R.  P.  M.,  185  lbs.  gauge  condensing 

pressure;  95.5    F.  Liquid  at  expansion  valve. 

5  lbs. 






5  lbs 






5  lbs. 






5  lbs. 






5  lbs. 






16.57  lbs. 






16.57  lbs. 






Vol.  Ill,  No.  5 





16.57  lbs. 






16.57  lbs. 






16.57  lbs. 






25  lbs. 






25  lbs. 






25  lbs. 


1 .55 




25  lbs. 






25  lbs. 






Series  XXV  and  XXVI.     Runs  461  to  498.     Single  acting  vs. 
Double  acting  compressors.    Compressor  I.  H.  P.  per  ton. 




5  lbs. 

16.57  lbs. 

25  lbs. 


in </f  of 










S.A     D.A. 

S.A.     D.A. 

S.A.     D.A. 

S.A.    D.A. 


0.24    .... 

1 .75     .... 

1.30     .... 

1.09     .... 


....     0.42 

....     2.18 

....     1.60 

....     1.26 


0.76    0.85 

1.77    2.34 

1.32     1.62 

1.10    1.28 


2.85    2.93 

1.82    2.56 

1.36    1.72 

1.12     1.35 


1.46    1.55 

1.81     2.45 

1.34    1.64 

1.11     1.30 


5.63    5.71 

1.83    2.89 

1.39    2.01 

1.13     1.44 

Series  XXV  and  XXVI.    Runs  461  to  498.     Single  acting  vs. 
double   acting   compressor.     Tonnage   per   24   hours. 















































Concerning  these  tests,  it  is  well  to  observe  that  they 
were  made  with  new  and  perfectly  fitted  pumps.  A  little  re- 
flection makes  it  clear  that  in  practical  use  the  wear  on  the 
horizontal  type  of  pump  will  be  much  greater  than  on  the 
vertical  type.  The  heavy  piston,  wearing  on  the  bottom  of 
the  horizontal  cylinder  soon  develops  a  leak  on  the  upper  side, 
causing  a  loss  of  efficiency  which  increases  in  proportion  to  tin' 
length  of  service.  At  the  same  time,  this  wear  on  the  bottom 
of  the  cylinder  tends  to  throw  the  piston  rod  out  of  line, 
so  that  the  wear  and  friction  on  the  stuffing  box  is  greatly 
increased,  thus  calling  for  a  corresponding  increase  in  power 



[May,  1911 

Fig.   3.      Cylinder   of   Single   Acting   Refrigerating   Machine. 

Vol.  Ill,  No.  2]    MECHANICAL  REFRIGERATION  :    MAHER  241 

required.  With  the  vertical  type  of  machine,  the  pistons  are 
perfectly  balanced  on  the  cross  head  and  there  is  little  per- 
ceptible, and  no  unequal,  wear  on  the  cylinders,  which  makes 
it  apparent  that  the  advantage  shown  in  favor  of  the  vertical 
type  of  pump  in  the  above  tests  grows  more  pronounced  in 
proportion  to  the  length  of  time  that  the  machines  are  in 

The  manufacturers  of  vertical  machines  have  always  con- 
tended that  it  was  impractical  to  compress  an  elastic  gas 
against  the  stuffing  box  and  their  contention  seems  to  have 
been  proven  in  the  above  tests. 

About  this  time  the  situation  was  further  aggravated  by 
the  fact  that  the  many  builders  of  horizontal  pumps,  striving 
amongst  themselves,  sought  to  meet  competition  and  overcome 
it  by  cutting  down  their  manufacturing  costs.  This  resulted 
in  cutting  out  material  wherever  possible,  at  the  same  time 
increasing  stresses  by  increasing  speeds,  all  with  a  reckless 
disregard  for  the  factor  of  safety,  and  encouraged  always  by 
the  indiscriminating  and  misinformed  buying  public,  with  its 
exaggerated  ideas  of  the  value  of  money  and  a  child-like  dis- 
regard for  the  element  of  hazard. 

The  laws  of  physics  cannot  prudently  lie  disregarded  nor 
can  Nature  be  outraged  with  impunity.  The  inevitable  hap- 
pened. We  commenced  to  hear  of  accidents — ammonia  ex- 
plosions (which  were  never  explosions,  but  defects  in  design 
and  construction  resulting  in  fracture  and  flooding  of  am- 
monia). Many  lives  of  innocent  victims — sometimes  a  dozen 
or  more  at  a  time — were  thus  sacrificed  to  ignorance  and  greed. 
It  is  not  easy  to  determine  which  is  the  more  culpable :  the 
purchaser  with  his  exaggerated  estimate  of  dollars,  or  the 
manufacturer  whose  greed  for  gain  caused  him  to  disregard 
his  responsibility  to  society. 

Reviewing  the  past  two  decades,  we  are  compelled  to  rec- 
ognize the  fact  that  much  that  has  been  classed  as  progress 
in  the  development  of  the  science  of  mechanical  refrigeration 
is  negative  progress;  essential  perhaps  in  the  process  of  evolu- 
tion, but  not  pleasant  to  review. 

It  is  interesting  to  know,  and  a  fact  that  may  be  reflected 
upon  with  profit,  that  the  one  company  which  has  been  most 
successful  financially  and  which  now  enjoys  the  most  enviable 
reputation  among  the  engineering  fraternity  is  the  one  and 
only  company  which  has  adhered  strictly  to  the  vertical  single 
acting  type  of  pump  and  has  refused  to  abandon  its  ideals  for 
temporary  pecuniary  advantage ;  while  most  of  those  which 
were  attracted  by  the  lure  of  gain  and  which  engaged  in  the 

248  THE   ARMOUR   ENGINEER  [May,  1911 

manufacture  of  the  cheaper  type  of  pump  have  generally 
reaped  bitter  disappointment.  A  few  have  achieved  temporary 
financial  success  in  a  very  moderate  degree,  but  their  future  is 
not  bright,  nor  can  their  past  record  be  a  source  of  very 
general  satisfaction. 

The  lines  of  divergence  are  becoming  more  clearly  de- 
fined, the  interested  public  are  thereby  enabled  to  gain  a  clearer 
understanding  of  the  subject,  and  are  coming  to  exercise  a 
greater  discrimination  in  the  purchase  of  their  equipment,  all 
of  which  is  most  encouraging  to  those  who  are  conscientious 
in  their  endeavor  and  who  believe  in  the  ultimate  success  of 
conscientious  effort. 

Until  within  the  past  two  years  there  has  been  little  change 
and  no  material  improvement  in  the  method  of  circulating  and 
expanding  ammonia  or  in  the  method  of  condensing.  The  most 
notable  departure  from  the  original  is  a  method  perfected  and 
adopted  by  the  Frick  Company  of  Waynesboro,  Pa.,  one  of  the 
oldest  and  best  known  manufacturers  of  refrigerating  machin- 
ery.   We  refer  to  what  they  call  their  "flooded  system." 

The  original  method  consisted  in  admitting  a  spray  of 
liquid  ammonia  into  the  expansion  coil  through  a  needle-point- 
ed valve  which  graduated  the  quantity  of  liquid  according  to 
the  operating  conditions.  In  practice  it  has  always  been  found 
difficult  to  regulate  the  quantity  of  liquid  admitted  owing  to 
the  varying  conditions  and  changes  in  temperature  experienced 
in  a  refrigerating  plant  in  operation,  and  much  annoyance  and 
loss  of  efficiency  has  resulted  on  this  account. 

With  tin1  Prick  Flooded. System,  the  liquid  ammonia  is  ad- 
mitted in  a  body  into  the  expansion  coils,  and  by  an  ingenious 
arrangement  is  held  in  the  coils  until  it  becomes  fully  vapor- 
ized. This  method  results  in  supplying  to  the  coils  the  maxi- 
mum amount  of  ammonia  that  can  lie  vaporized  at  all  times  and 
under  all  conditions,  and  makes  unnecessary  the  close  regula- 
tion and  continual  readjustment  required  in  the  old  system.  Tn 
practice  it  is  found  that  the  efficiency  of  the  cooling  surface 
represented  by  expansion  coils  is  increased  from  25ffl  to  33  1/3 
°7<  with  the  application  of  this  improved  method. 

The  scope  of  this  article  will  not  permit  of  a  detailed  ex- 
planation of  the  many  and  varied  applications  of  mechanical 
refrigeration  as  employed  in  the  various  departments  of  manu- 
facture and  production    in  which  it  has  proven  practical. 

Tn  the  manufacture  of  ice,  the  cooling  of  rooms  in  which 
provisions  are  stored,  sometimes  for  months ;  in  the  re-hydrat- 
ing  of  air  used  by  steel  mills  in  blast  furnaces  for  the  manufac- 

Vol.  Ill,  NO.  2]    MECHANICAL  REFRIGERATION:    MAHEK  245) 

ture  of  steel  billets;  in  the  manufacture  of  agricultural  imple- 
ments ;  in  the  chilling  of  iron ;  in  horticulture — for  the  preserva- 
tion of  flowers,  bulbs  and  fruits ;  in  the  transportation  of  tropi- 
cal fruits  in  vessels  and  cars  by  means  of  which  ripening  is 
retarded  so  that  the  fruit  does  not  become  over-ripe  or  decayed 
in  transit ;  for  the  freezing  of  fish  and  other  sea  foods ;  in 
the  manufacture  of  explosives  for  reducing  the  temperature  of 
the  chemicals  during  the  mixing  process  by  which  the  danger 
of  premature  explosion  is  eliminated ;  in  heavy  construction 
work  where  quicksand  is  encountered  in  tunnelling  or  sinking 
shafts,  or  in  laying  foundations,  freezing  the  quicksand  so  that 
it  may  be  taken  out  in  solid  blocks ;  in  surgery  and  medicine ;  in 
the  pasteurizing  of  milk  and  other  food  products ;  in  the  preser- 
vation of  valuable  furs;  in  the  manufacture  of  films  used  for 
photography;  in  the  manufacture  of  glue  and  soap;  and  in  the 
process  of  refining  petroleum.  All  of  these  processes  are  in- 
tensely interesting  to  the  student  of  engineering  and  offer  the 
widest  possible  opportunity  for  the  exercise  of  ingenuity,  since 
every  refrigeration  installation  requires  a  different  arrange- 
ment and  a  different  readjustment  of  proportions  to  suit  the 
local  conditions  and  meet  the  requirements  of  the  particular 
duty  demanded. 

In  the  installations  of  the  last  twenty  years  or  more  the 
writer  does  not  know  of  two  ice  plants  or  two  refrigerating 
plants  that  are  exactly  alike  in  every  detail.  Some  new  condi- 
tion or  combination  is  always  present  in  each  individual  instal- 
lation, presenting  new  problems  to  be  worked  out  and  offering 
unlimited  opportunity  and  encouragement  to  the  engineer  for 
the  exercise  of  all  of  his  natural  ingenuity  and  for  all  the 
knowledge  and  wisdom  that  he  may  have  acquired. 

If  we  have  succeeded  in  making  clear  the  fundamental 
principles  upon  which  the  science  of  refrigeration  is  based,  and 
if  in  reviewing  the  history  of  its  industrial  development,  in 
which  we  have  pointed  to  the  mistakes  that  have  been  made; 
we  have  warned  any  who  may  come  after  us,  then  we  have  ac- 
complished our  purpose.  At  the  same  time,  we  shall  be  grati- 
fied if  we  have  inspired  in  the  minds  of  any  of  the  coming  gen- 
eration of  engineers  that  respect  for  high  ideals,  and  that  con- 
fidence in  ultimate  success  of  those,  who  having  high  ideals 
adhere  to  them,  and  consistently  refuse  to  offer  to  the  world 
anything  less  than  the  very  best  of  which  they  are  capable,  al- 
ways striving  toward  perfection,  thus  realizing  life's  purpose 
and  its  grand  possibilities. 

the  Mcmullen  process  for  sugar  manufacture 


The  development  of  any  new  process  based  on  chemical 
principles  will  occur  in  the  way  of,  first,  the  idea,  the  experi- 
mental or  laboratory  period,  then  the  factory  or  commercial 
period.  Having  been  rather  closely  identified  with  the  de- 
velopment of  this  process,  perhaps  I  can  trace  all  the  steps 
in  the  evolution  of  this  method  of  sugar  manufacture. 

Mr.  McMullen  and  his  associates  had  been  working  for  a 
number  of  years  on  a  method  for  drying  sugar  beets  and  ex- 
tracting the  sugar  from  them  at  any  convenient  time.  This 
had  been  brought  to  a  successful  termination  in  the  laboratory, 
when  one  day  Mr.  McMullen  came  to  me  saying  that  he  be- 
lieved the  sugar  cane  offered  a  greater  field  for  the  applica- 
tion of  the  new  process,  than  did  the  sugar  beet.  We  dis- 
cussed the  question  for  some  time,  and  went  over  the  avail- 
able literature  on  the  subject  of  cane  composition,  cane  and 
sugar  yields  per  acre  in  various  countries,  and  losses  in  the 
present  processes,  which  we  deemed  would  be  avoided  in  the 
new  process. 

Yields  of  Cane  and  Sugar  in  Various  Localities. 

Locality         Tons  Cane  Tons  sugar         Pounds  Cane 

per  acre.  per  acre.             per  lb.  Sugar. 

Barbados 36  2.90                         12.4 

Louisiana 2G  2.49                         11.8 

Mauritius 2.25 

Queensland 2.30 

Sandwich  Is. .  .  .  2.43 

Same    irrigated  6.11 

As  we  looked  into  the  subject,  we  noted  the  high  sugar 
content  of  the  tropical  cane  as  compared  with  the  sugar  beet : 
we  noted  the  amount  of  cellulose  present  in  the  cane  which 
would  be  available  for  the  cellulose  industries  as  soon  as  the 
sugar  had  been  completely  extracted,  and  also  thought  we 
saw  how  cane  sugar  could  be  made  without  a  refinery. 

♦Professor   of  Chemical    Engineering.     Armour  Institute   of  Technology. 

Vol.  Ill,  No.  2]    SUGAR  MANUFACTURE  :    McCORMACK  251 

Average  Composition  of  Cane. 

Water 71.04  per  cent 

Sugar 18.02  per  cent 

Cellulose 9.56  per  cent. 

Albuminous 0.55  per  cent. 

Fatty  and  Coloring 0.35  per  cent. 

Mineral  matter 0.48  per  cent. 

We  found  in  the  literature  descriptions  of  previous  at- 
tempts to  extract  the  sugar  from  cane  by  diffusion,  and  while 
these  attempts  had  not  gone  to  successful  commercial  termin7 
ation,  we  could  not  see  anything  very  discouraging  in  the  ac- 
counts  given. 

Newlands,  in  his  Handbook  on  Sugar,  gives  the  following 
historical  accounts  of  diffusion  processes  as  applied  to  the 

"Although  borrowed  from  the  earliest  stage  of  the  beet- 
root industry,  it  was  not  till  1843  that  the  operation  of  slicing 
was  applied  to  the  sugar-cane.  It  was  hoped  that  the  cane, 
after  having  been  sliced,  dried,  and  ground  to  powder,  might 
be  preserved  long  enough  unchanged  in  this  condition  to  al- 
low of  its  being  transported  to  Europe,  where  not  merely  the 
whole  sugar  might  be  extracted  at  once  in  its  purest  form,  but 
the  ligneous  portion  would  furnish  an  inexhaustible  supply  of 
fibre  for  the  paper  market.  The  dried  cane  powder,  however, 
became  altered  on  the  voyage,  and  not  only  did  great  part  of 
the  sugar  disappear,  but  the  changes  consequent  on  its  de- 
composition discoloured  the  residuary  fibre.  But  there  was 
one  result  from  this  trial  sufficiently  noteworthy.  It  was 
clear  that  the  cane  could  be  sliced  and  dried  in  commercial 
quantities,  and  several  of  those  concerned  in  the  matter  de- 
termined to  extract  the  sugar  on  the  spot;  accordingly,  more 
than  one  attempt  was  made  to  carry  out  the  slicing,  and  ap- 
parently every  obstacle  was  overcome,  when  the  building  erect- 
ed for  the  plant,  was,  unfortunately,  burned. 

One  of  the  principal  difficulties  hitherto  had  been  that  of 
drying  the  sliced  cane;  to  avoid  this,  in  1845  Constable  and 
Michel  introduced  their  method  on  the  estate  of  Ste.  Marie, 
the  property  of  Major  Bousearen,  in  Guadeloupe.  It  was  as 
follows:  The  canes  which  were  sliced  at  the  rate  of  1  ton  in 
twenty  minutes,  fell  into  metallic  baskets,  each  capable  of 
holding  that  amount.     The  baskets  were  moved  by  a  central 

252  THE  ARMOUR  ENGINEER  [May,  1911 

crane,  and  around  the  crane,  at  equal  distances,  were  placed 
6  copper  vessels,  adjusted  to  receive  the  baskets  when  filled. 
These  copper  vessels  were  filled  to  such  an  extent  with  water 
that  when  the  basket,  full  of  sliced  canes,  was  lowered  into 
any  one,  the  liquid  rose  to  the  surface.  The  basket  No.  1,  with 
its  contents,  having  been  thus  dipped  into  vessel  No.  1,  was 
allowed  to  remain  immersed  till  such  time  as  the  sliced  canes 
had  parted  (by  displacement)  with  a  due  proportion  of  their 
sugar  to  the  water  in  vessel  No.  1 ;  basket  No.  1  was  then  hoist- 
ed out  by  the  crane,  and  consigned  to  vessel  No.  2,  where  a 
second  proportion  of  sugar  was  displaced ;  and  so  on  through- 
out the  series.  In  the  meantime,  a  fresh  basket  full  of  sliced 
cane  was  consigned  to  No.  1  vessel,  the  liquid  in  which  ex- 
tracted a  further  proportion  of  sugar,  and  so  on,  till  the  con- 
tents of  the  first  vessel  were  as  fully  saturated  with  sugar  as 
the  law  of  displacement  allowed  and  the  slices  of  cane  in  the 
first  basket  were  proportionately  exhausted. 

This  was  virtually  the  old  system  of  Dubrunfaut  with  its 
defects,  viz.,  that  the  water  was  not  easily  kept  at  a  suitable 
temperature  ;  that  the  whole  sugar  was  not  extracted ;  and  that, 
from  the  time  which  elapsed  between  slicing  and  exhaustion, 
considerable  changes  occurred  in  the  saccharine  fluid,  which 
affected  the  quantity  and  quality  of  the  result.  These  defects 
in  principle  did  not,  however,  of  themselves  contribute  much 
to  the  failure  of  the  plan ;  the  system  broke  down  in  the  subse- 
quent evaporation,  in  which  the  heat  employed  was  generated 
entirely  from  gas  manufactured  on  the  spot — an  operation  at- 
tended with  such  difficulties,  that  the  trials  were  given  up  af- 
ter heavy  outlay.  This  was  much  to  be  regretted,  as  the  slic- 
ing process  had  shown  that  a  much  larger  proportion  of  the 
sugar  could  be  extracted  from  the  cane  than  had  been  hither- 
to done  in  any  other  way. 

A  system  so  simple  and  yet  promising  such  complete  re- 
sults was  not  destined  to  disappear  without  leaving  traces.  In 
Sept.,  1847,  Davier,  apothecary-in-chief  to  the  French  service 
at  Basseterre,  resumed  the  experiments  of  slicing  and  drying 
the  canes,  at  the  point  where  they  had  left  off  in  1845.  He 
found  that  by  driving  off  about  33  per  cent  of  moisture  from 
sliced  canes  they  became  so  friable  as  to  be  reduced,  without 
difficulty,  to  a  coarse  powder  in  which  the  colouring  matter 
and  albumenoid  principles  of  the  cane  had  become  insoluble 
in  water,  while  the  saccharine  elements  were  crystalized  un- 
changed and  ready  for  immediate  solution  and  extraction  by 

Vol.  Ill,  No.  2]    SUGAR  MANUFACTURE  :    McCORMACK  253 

either  hot  or  cold  water.  The  former  w,ould  have  been  the 
more  rapid,  but  he  met  with  an  objection  to  its  use,  which,  if 
not  scientific,  was  at  least  practical.  The  vessels  he  employed 
were  of  copper,  and  transmitted  heat  so  rapidly  that  the  at- 
tendants were  constantly  burning  their  fingers;  he  did  not 
consider  it  worth  while  to  take  any  precautions  to  avoid  this 
evil,  as  he  found  cold  water  sufficient  for  this  purpose,  and 
more  economical.  The  process  he  adopted  was  the  following : 
Six  upright  cylinders  of  copper;  about  4  ft.  high  and  9  inches 
in  diameter,  were  so  arranged  as  to  communicate  with  each 
other,  and  with  a  reservoir  of  water  on  a  higher  level;  they 
were  each  furnished  with  gauges  and  stopcocks ;  five  of  these 
were  filled  with  cane  powder,  and  the  last  with  animal  char- 
coal— this  was  merely  precautionary,  but  not  essential  to  the 
work.  Water  was  admitted  into  No.  1,  and  retained  there  for 
twenty  minutes  after  the  gauge  showed  that  the  vessel  was 
full ;  it  was  then  passed  into  No.  2,  and  so  on.  In  practice,  it 
was  found  that,  on  escaping  from  No.  4,  the  water  had  ab- 
sorbed so  much  sugar  as  to  mark  22.5°B.,  or  about  the  density 
when  syrup  is  usually  consigned  to  the  vacuum-pan;  and  that 
the  cane  powder  first  in  contact  with  the  water,  viz.,  that 
in  No.  1,  was  completely  exhausted,  even  to  the  taste,  that 
most  convenient  and  reliable  saccharometer,  and  represented 
what  it  was  reduced  to  in  reality — a  mass  of  wet  sawdust.  At 
this  stage  of  the  process,  it  was  removed  from  No.  1,  and  re- 
placed by  a  fresh  portion  of  cane  powder.  As  this  part  of  the 
operation  was  performed  without  interrupting  the  duties  of 
the  other  cylinders,  it  is  clear  that  two  of  the  greatest  de- 
siderata had  been  attained,  namely,  the  complete  extraction  of 
the  sugar  in  a  state  of  purity,  and  that  by  a  continuous  opera- 

The  mechanism  thus  employed  by  Davier  in  September 
1847  appeared  to  leave  little  room  for  improvement.  It  was 
submitted  to,  and  approved  by  the  French  government,  who 
commissioned  the  inventor  to  repair  to  Paris  in  the  ensuing 
month  of  March  to  take  the  necessary  steps  for  erecting  a 
set  of  machinery  on  a  larger  scale  on  the  French  King's  estate 
of  Tremoiullant,  in  Martinique.  Fortune  seemed  about  to 
crown  Daviers  laborious  and  successful  trials,  when  the  French 
Revolution  intervened  and  the  new  process  was  shelved. 

Since  that  date,  the  Hon.  EL  S.  Mitchell,  has  several  times, 
in  conjunction  with  IT.  Warner,  repeated  the  process  of  slicing 
and  drying  the  sno-ar-cane.  with  evactly  similar  results,  name- 
lv,  the  extraction  of  all  the  contained  sugar  by  displacement 

254  THE  ARMOUR  ENGINEER  [May,  1911 

with  cold  water  in  about  1  hour  and  20  minutes,  in  the  form 
of  a  pure  syrup,  marking  between  22°  and  23°  B. 

Warner  next  directed  his  attention  to  the  slicing  of  the 
cane,  to  ascertain  how  far  he  could  succeed  in  extracting  the 
sugar  without  recourse  to  drying  the  slices.  After  repeated 
trials,  conducted  with  every  precaution,  he  succeeded  in  ob- 
taining, by  displacement,  a  liquor  marking  9°B.  This  was  a 
great  success,  but  not  equal  in  results  to  the  mode  where  the 
slices  were  dried,because  there  was  not  only  an  original  loss 
in  obtaining  the  whole  sugar,  but  the  juice  had  an  opportunity 
of  becoming  changed  to  an  extent  that  greatly  increased  the 
quantity  of  uncrystallisable  sugar.  This  latter  evil  was  miti- 
gated by  the  use  of  small  doses  of  antiseptics  in  the  displacing 
water,  so  as  to  preserve  the  juice  unchanged  throughout  the 
process  of  manufacture." 

Newlands  also  describes  some  later  experiments  on  dif- 
fusion processes  in  which  the  object  is  to  enrich  the  juices  ob- 
tained in  crushing  by  passing  them  through  a  diffusion  bat- 
tery containing  fresh  crushed  cane.  He  dismisses  the  subject 
of  diffusion,  however,  with  the  statement: 

"Looked  at  simply  as  a  process  for  extracting  a  large  per- 
centage of  sugar  from  the  cane,  diffusion  is  beyond  question, 
a  great  success,  but  most  planters  are  more  anxious  to  make 
money  than  to  make  sugar,  and  consequenntly,  the  whole  mat- 
ter depends  on  the  question — will  it  pay?  This  in  turn,  hinges 
almost  entirely  on  the  question  of  fuel." 

We  thought  however,  that  the  question  of  fuel  was  not 
the  paramount  one,  as  it  seemed  very  poor  economy  to  use 
cellulose,  valued  certainly  at  one  cent  a  pound,  for  fuel,  when 
its  cash  value  as  fuel  is  about  $1.25  per  ton,  with  coal  at  the 
price  it  brings  in  Cuba. 

We  note  in  the  earlier  experiments  some  points  indicating 
the  advantage  of  treating  the  cane  in  some  such  way.  For 
example,  the  experiments  of  Davier,  made  in  1847  showed  that 
cane  could  be  dried  without  material  change  in  its  sugar  con- 
tent; that  the  powdered  dry  cane  could  be  made  sugar-less  in 
six  changes  of  water ;  that  the  juice  had  a  high  purity,  and 
that  its  sugar  content  was  satisfactorily  high. 

It  is  striking  that  the  literature  of  sugar  should  contain 
an  account  of  such  a  process,  for  nearly  sixty  years  without 
other  attempts  being  made  to  bring  it  to  a  satisfactory  conclu- 
sion. And  during  all  this  time,  there  were  no  changes  of  any 
revolutionary  character  in  the  industry.  It  is  true  that  in  the 
cane  sugar  industry  there  was  considerable  progress  in     the 

Vol.  Ill,  No.  2|    SUGAR  MANUFACTURE :    McCORMACK  25fi 

mechanical  equipment  of  a  sugar  mill,  and  that  the  cost  of  re- 
fining raw  sugar,  has  been  decreased  a  few  fractions  of  a  cent, 
but  the  mills  and  factories  were  yet  idle  forty  percent  of  the 
time,  and  all  the  cane  sugar  was  marketed  as  raw  sugar  having 
yet  to  be  subjected  to  refining. 

Our  first  experimental  work  was  done  on  fifty  pounds  of 
cane  secured  from  Mexico,  and  which  was  about  three  weeks 
on  the  road,  consequently  not  arriving  in  the  best  of  condi- 
tion. At  this  time,  too,  we  had  no  satisfactory  method  of 
shredding  the  cane;  the  first  lot  was  chipped  up  by  fastening 
it  in  a  carpenter's  vise,  and  shaving  it  with  a  draw  knife.  Our 
work  showed  us  at  once,  however,  that  the  cane  could  be 
satisfactorily  dried,  and  that  we  could  get  a  rich  and  pure 
sugar  juice  from  it,  provided  the  sugar  content  of  the  cane 
was  right  when  we  started  with  it.  In  other  words  we  proved 
that  the  dried  cane  could  be  prepared  with  its  sugar  content 
unchanged  by  the  drying  operation. 

We  next  went  on  a  search  for  a  satisfactory  cane  shredder, 
and  found  one  being  operated  on  the  Louisiana  plantation  of 
Ex-Gov.  Warmouth.  shredding  the  cane  for  the  only  cane 
factory  where  the  diffusion  process  is  in  use.  A  small  ma- 
chine of  this  type  was  built;  the  drier  which  we  had  been  using 
on  beets,  was  brought  to  Chicago,  and  thirty  tons  of  Louisi- 
ana cane  were  secured  for  the  drying  experiment.  Enough 
cane  was  dried  to  enable  us  to  make  an  estimate  on  the  cost 
of  drying,  and  to  supply  us  with  sufficient  material  for  dif- 
fusion to  obtain  the  sugar  juices,  and  the  exhausted  material 
for  paper  stock. 

Our  results  were  not  always  just  as  we  would  have  liked, 
but  they  were  of  such  a  nature  as  to  convince  us  that  the  pro- 
cess would  be  a  commercial  success.  The  sugar  juices  were 
of  higher  purity  than  those  we  could  obtain  directly  from 
the  cane,  the  diffusion  could  be  so  regulated  as  to  give  us  a 
sugar  juice  of  any  concentration  desired,  and  the  exhausted 
cane  made  excellent  paper. 

We  then  thought  that  our  results  justified  work  on  a 
commercial  scale,  so  a  site  was  secured  on  a  large  Cuban 
plantation  and  a  factory  built  to  dry  500  tons  of  cane  per 

The  operation  of  this  plant  will  be  described.  The  cane 
comes  from  the  field  to  the  factory  on  flat  cars,  and  is  trans- 
ferred from  the  cars  directly  to  the  runway  of  the  shredder. 
The  shredder  consists  of  a  toothed  cylinder  about  8  feet  long, 
the  cane  being  fed  to  it  by  a  star     feed.     The     cane     passing 

25G  THE  ARMOUR  ENGINEER  [May,  1911 

through  the  shredder  is  cut  up  into  particles  about  like  fine 
excelsior,  falls  on  a  belt  and  is  carried  up  to  the  hopper  of 
the  drier.  The  shredded  material  is  fed  from  the  hopper  over 
a  hollow  steam  heated  roller,  and  goes  on  to  the  first  belt  of 
the  drier,  at  a  temperature  of  about  98°  C. 

The  drier  consists  of  twenty  belts,  50  feet  long  and  12 
feet  wide,  one  over  the  other,  moving  in  opposite  directions,  and 
the  material  falling  from  the  upper  one  to  the  one  next  below. 
Steam  heating  pipes  are  placed  between  the  upper  and  lower 
portions  of  each  belt,  and  an  air  current,  maintained  by  a 
suction  fan,  is  circulated  by  means  of  baffle  boards,  across  each 

The  temperature  from  belt  to  belt  is  gradually  lowered, 
as  the  moisture  content  of  the  cane  lowers,  so  that  the  final 
drying  is  done  at  a  temperature  of  about  85°  C. 

We  formerly  had  the  idea  that  all  the  drying  must  be  done 
with  the  air  temperature  under  the  boiling  point  of  water; 
this  was  proved  erroneous  by  sending  some  wet  cane  through 
a  direct  heat  drier  with  a  flame  temperature  of  1100°  C.  We 
still  think  however  that  the  final  drying  must  be  done  at  a 
low  temperature. 

The  cane  goes  in  with  a  moisture  content  of  about  70  and 
comes  out  with  about  1.  The  cost  of  drying  has  been  about 
$1.10  per  ton.  The  dried  material  is  screened  to  separate  cane 
fibre  from  cane  pith,  and  the  separated  products  go  to  the 
baling  presses  to  be  prepared  for  shipment. 

The  products  undergo  this  primary  separation  on  account 
of  their  properties.  The  paper  makers  had  considerable 
trouble  in  the  past  because  the  two  materials  behave  so  dif- 
ferently on  cooking.  The  fibre  can  now  be  used  alone,  mak- 
ing a  soft  white  paper,  while  the  pith  will  find  its  chief  use  in 
the  nitro-cellulose  industries  as  it  nitrates  very  readily  and 
washes  very  satisfactorily. 

The  cane  yields  about  33  per  cent  fibre  and  about  66  per 
cent  sucrose  and  10  per  cent  cellulose.  The  pith  contains 
about  57  percent  sucrose  and  25  percent  cellulose.  The  pith 
presses  so  firmly  that  it  will  bear  transportation  any  distance 
without  covering ;  the  fibre,  however,  must  be  baled  like  a  cot- 
ton bale.  The  products  are  now  loaded  on  boat,  and  trans- 
ported to  any  convenient  factory  for  the  extraction  of  the  su- 
gar. At  the  factory  the  bales  are  broken  up,  the  dry  ma- 
terial passed  through  a  mixer,  where  dilute  sugar  juice  is 
added    until  the  material  is  just  saturated  with  water,     and 

Vol.  Ill,  No.  2]    SUGAR  MANUFACTURE  :    MoCORMACK  257 

then  passed  to  a  continuous  centrifuge  for  the  extraction  of 
the  sugar.  In  the  front  portion  of  the  machine,  the  concen- 
trated sugar  juice  is  taken  off.  in  the  posterior  portion  the 
material  is  sprayed  with  water,  yielding  a  dilute  sugar  juice 
which  is  employed  to  moisten  fresh  cane.  The  cane  coming 
from  the  centrifuge  is  sugarless,  yielding  no  test  for  sugar  with 
sulphuric  acid  and  B  napthol.  It  is  calculated  that  an  indi- 
vidual particle  of  cane  will  pass  through  the  centrifuge  in 
1/100  part  of  a  second.  The  extracted  cane  is  ready  for  use 
in  the  cellulose  industries  while  the  sugar  juices  are  treated 
about  the  same  as  the  beet  juices  are  in  a  beet  sugar  factory, 
except  that  the  juices  are  sent  to  the  triple  effect  slightly 
acid  instead  of  slightly  alkaline.  The  saving  on  evaporation 
is  considerable  as  we  can  easily  handle  a  22°  Brix  solution 
from  the  centrifuge  while  the  juice  in  the  ordinary  factory  will 
run  from  10  to  12°  Brix  on  the  juice  from  the  rolls.  The 
plantation  upon  which  we  have  our  drier  secured  a  yield  just 
under  80  percent  of  the  sugar  content  of  the  cane  in  their  mill 
last  year.  This  was  obtained  by  passing  the  cane  through 
three  sets  of  three  rolls  each  and  macerating  with  water  be- 
tween the  sets  of  rolls.  This  meant  a  sugar  loss  on  this  one 
plantation  of  19,000  tons. 

I  would  sum  up  the  advantages  of  the  McMullen  process 
as  follows: 

(a)  Enables  the  factory  to  be  located  where  fuel  and 
labor  conditions  are  most  satisfactory,  and  to  operate  con- 

(b)  Secures  all  of  the  sugar  from  the  cane,  not  eighty 
percent  of  it. 

(c)  Saves  about  50  percent  of  the  evaporation  cost  on 
the  sugar  juice. 

(d)  Makes  available  for  the  cellulose  industries  one 
half  pound  of  cellulose  for  every  pound  of  cane  sugar  made. 

(e)  Places  refined  sugar  on  the  market  without  interven- 
tion of  a  refinery. 

We  all  know  that  the  final  test  for  any  new  process  is  "will 
it  pay?"  1  can  best  answer  this  by  concluding  with  a  tabu- 
lated statement  taken  from  the  books  of  a  typical  Cuban 
plantation  and  their  estimate,  not  ours,  of  the  profits  accruing 
from  the  adoption  of  the  new  process. 

258  THE   ARMOUR  ENGINEER  I  M.iy,  l!>l  I 

Report  of  a  Typical  Cuban  Plantation. 

Actual  results  in  1910.  Estimate  for  McMullen  process. 

633,220  tons    cane  at    factory, 

@  $2.50  per  ton $1,592,512.81         .  .$1,592,512.81 

Expenses  connected  with  mfg. 

freight,  etc 2,559,475.79        .  .   2,480,884.67 

Selling  expense 58,748.70        .  .      108,719.78 

Total  Cost $  4,208,737.30       .  .$4,182,117.26 

Raw  Sugar  &  Molasses 
137,196,740  lbs.&  2,870,334  gals     Refined   Sugar 

165,488,414  lbs.  8,374,420.70 
$5,880,812.74  Molasses  2,000,000  gals 

125,000,000  lbs.  fibre$l,250,000.00 

Total  value $9,624,420.70 


$  1,672,075.44  $5,442,303.44 

Additional  profit  per  ton  cane  by  McMullen  Process.  .$5.95 


The  Semi-Annual  Technical  Publication  of  the  Student  Body  of 

VOL.  Ill  CHICAGO,  MAY,  1911  NO.  2 

Publishing  Staff  for  the  year  1911: 

C.  W.  Binder,  Editor. 

G.  H.  Emin,  Business  Manager.  L.  H.  Roller,  Assistant  Editor. 

M.  A.  Peiser,  Associate  Business  Manager. 

Board  of  Associate  Editors: 

H.  M.  Raymond,  Dean  of  the  Engineering  Studies. 
L.  C.  Monin,  Dean  of  the  Cultural  Studies. 
G.  F.  Gebhardt,  Professor  of  Mechanical  Engineering. 
E.  H.  Freeman,  Professor  of  Electrical  Engineering. 

Terms  of  Subscription: 

The  Armour  Engineer,  two  issues,  postage  prepaid $1.00  per  annum 

Single  Copies 50  cents 

Published  twice  each  year,  in  January  and  in  May. 


In  view  of  the  interest  and  enthusiasm  manifested  in  the 
meetings  of  our  student  engineering  societies  this  past  year, 
we  are  prompted  at  this  time  to  add  a  few  words  which  we 
trust  will  stimulate  in  the  minds  of  the  undergraduates  a  little 
of  the  zeal  for  the  work  of  these  organizations  that  has  char- 
acterized the  meetings  of  the  past  year.  Obviously  it  would 
be  difficult  in  these  few  lines  to  dwell  on  all  of  the  advantages 
that  are  to  be  derived  from  affiliation  with  the  engineering 
society  in  his  chosen  line  of  work,  but  there  are  a  few  which 
are  particularly  important  and  which  may  be  profitably 

In  the  change  from  the  theoretical  work  of  the  classroom 
to  the  more  practical  work  of  the  profession,  the  graduate 
invariably  finds  himself  in  a  position  far  removed  from  that 
previously  conceived.  He  is  apt  to  find  himself  in  the  breach 
which  men  of  experience  tell  us  exists  between  college  life 
and  practical  life,  and  up  against  problems  which  doubtless 
were  never  considered  in  the  classroom.  While  this  period 
for  most  men  is  of  comparatively  short  duration,  yet  it  might 
be  further  lessened  had  the  graduate  been  connected  with  his 

260  THE  ARMOUR  ENGINEER  [May,  1911 

engineering  society,  in  which  he  would  have  received  advice 
that  would  have  enabled  him  to  better  comprehend  the  actual 
conditions  to  be  encountered. 

In  the  various  meetings  at  which  practising  engineers 
are  the  speakers,  both  students  and  faculty  members  are  kept 
in  touch  with  present  practice  and  recent  developments  in 
engineering  work,  and  become  acquainted  with  modern  meth- 
ods of  solving  the  technical  problems  of  the  day.  Not  only 
from  the  actual  technical  knowledge  diffused  is  the  student 
benefited,  but  in  getting  the  broader  aspect  of  engineering 
work  at  large,  thus  making  him  realize  that  his  school  train- 
ing is  being  conducted  along  definite  and  effective  lines,  and 
consequently  giving  him  a  greater  incentive  for  the  work  to 
come.  In  addition  to  this — and  possibly  of  more  immediate 
importance  to  the  student — are  the  words  of  practical  advice 
coming  from  these  men  of  recognized  standing  in  the  engi- 
neering world,  advice  which  does  much  toward  giving  him  a 
more  adequate  conception  of  the  career  for  which  he  is 

Another  source  of  development  coming  to  a  man  through 
the  engineering  society  is  his  being  assigned  an  evening  on 
which  to  lecture  regarding  some  particular  phase  of  work  in 
which  he  is  particularly  interested.  The  confidence  inspired, 
and  the  help  received  in  the  discussions  which  follow,  neces- 
sitating a  practice  of  being  able  to  express  himself  in  a  clear 
and  forceful  manner,  are  far  more  advantageous  than  to  be 
able  to  make  a  creditable  recitation  in  the  classroom.  More- 
over, in  the  reading  of  a  paper  and  subsequent  discussion  the 
listeners  as  well  as  speaker  are  usually  found  in  a  more  active 
state  of  mind  than  is  usually  found  in  the  classroom,  and  so 
are  in  a  better  position  to  retain  any  valuable  impressions  that 
may  be  given. 

Particularly,  however,  do  we  wish  to  emphasize  the  help 
derived  from  listening  to  the  ''heart  to  heart"  talks  of  the 
men  who  have  been  there  and  who  know.  After  having  lis- 
tened to  a  few  of  these,  as  we  have  had  the  pleasure  of  doing 
in  the  past  year's  meetings,  the  graduate  will  have  that  which 
will  serve  him  well  in  that  trying  period  just  after  graduation. 

Vol.  Ill,  No.  2]  ENGINEERING  SOCIETIES  261 


On  the  evening  of  December  6,  1911,  Mr.  T.  L.  Condron, 
Mem.  A.  S.  C.  E.,  of  Condron  &  Sinks,  Civil  Engineers,  gave  an 
illustrated  lecture  on  '"Reinforced  Concrete  Buildings"  before 
the  members  of  the  Civil  Engineering  Society.  Mr.  Condron 
had  many  excellent  slides  showing  all  phases  of  this  class  of 
building  work,  and  in  the  course  of  his  remarks  paid  special 
attention  to  the  layout  of  plants,  and  to  the  best  and  most 
economical  methods  of  handling  and  placing  the  concrete  and 
steel  in  the  forms.  Tests  of  various  methods  of  floor  and  col- 
umn reinforcements  were  also  illustrated  and  discussed  by  Mr. 

The  meeting  on  Tuesday  evening,  February  21,  1911,  had  for 
its  lecturer  Mr.  Will  P.  Blair,  Secretary  of  the  National  Asso- 
ciation of  Paving  Brick  Manufacturers,  of  Indianapolis,  Ind. 
This  Association  is  engaged  in  an  educational  campaign  in  re- 
gard to  the  use  of  vitrified  brick  for  paving  purposes,  Mr.  Blair 
having  lectured  at  many  of  the  western  colleges  and  technical 
schools  along  this  line.  He  described  and  illustrated  with  ster- 
eopticon  slides  all  the  processes  (both  new  and  old)  in  connec- 
tion with  the  manufacture  of  brick  — especially  paving  brick. 
The  Association's  standard  specifications  for  materials  and  con- 
struction were  described.  The  necessity  of  a  proper  foundation 
was  emphasized  as  well  as  the  selection  of  a  suitable  and  dura- 
ble filler — the  Association  advocating  the  use  of  a  Portland  ce- 
ment filler  instead  of  a  bituminous  filler. 

On  March  7,  1911,  the  speaker  was  Mr.  Henry  R.  Matthei, 
an  Armour  graduate  of  the  class  of  1908.  Mr.  Matthei,  who 
has  been  here  on  a  leave  of  absence  from  the  Philippines,  spoke 
on  "Surveying  in  the  Philippines."  The  methods  and  proced- 
ure of  the  various  government  departments,  particularly  in  re- 
gard to  the  extensive  surveys  now  being  carried  on  in  the  Phil- 
ippine Islands,  were  described  and  discussed. 

Mr.  John  Ericson,  City  Engineer  of  Chicago,  gave  an  in- 
teresting talk  before  the  Society  on  the  evening  of  March  21, 
.1911.  Mr.  Ericson 's  talk  was  truly  what  he  said  it  would  be 
in  his  introduction,  "a  heart-to-heart  talk,"  full  of  personal 
experiences,  general  hints  and  advice  to  the  young  engineer. 

On  April  4,  1911,  Mr.  Carpenter,  of  the  Chicago  office  of 
the  U.  S.  Reclamation  Service,  gave  an  interesting  illustrated 
lecture  on  the  various  projects  of  this  part  of  the  Government's 
work.  The  lands  being  reclaimed  were  described  in  word  and 
picture  both  before  and  after  irrigation;  the  changes  accom- 
plished are  truly  marvelous.     Especially  interesting  were  the 

262  THE  ARMOUR  ENGINEER  [May,  1911 

descriptions   and   illustrations   of  the   engineering  features   in 
connection  with  this  work. 

The  last  meeting  of  the  year  was  held  on  Tuesday  evening, 
April  18,  1911,  with  Mr.  Onward  Bates,  Mem.  A.  S*  C.  E.,  of 
Bates  &  Kogers,  Engineers  and  Contractors,  as  the  speaker. 
Mr.  Bates  gave  an  interesting  talk  on  "The  Engineer  as  a  Man." 
directed  mainly  to  the  Seniors  about  to  graduate.  Specializa- 
tion in  a  particular  line  that  one  enjoys  or  is  fitted  tor  was 
recommended,  and  several  good  reasons  advanced  why  this 
should  be  done.  Two  classes  of  engineers  were  described,  those 
who  make  the  problems  and  those  who  work  them  out,  and  "it 
often  takes  a  better  man  to  make  the  problems  than  to  work 
them  out."  Thoroughness,  reliability,  good  sense  and  judg- 
ment, coupled  with  engineering  knowledge,  make  the  success- 
ful engineer.  Judgment  of  men  is  also  a  requisite  qualifica- 
tion necessary  for  an  engineer,  because  one  cannot  always  ' '  get 
men  that  come  up  to  specifications."  The  engineer  as  a  lawyer 
and  financier  was  discussed,  and  the  opinion  expressed  that 
the  engineer  ought  to  do  his  own  talking,  instead  of  hiring  it 
done ;  likewise  he  should  finance  his  work  — in  other  words,  be 
able  to  start  things  as  well  as  carry  them  out."  The  personal 
incidents  and  experiences  which  Mr.  Bates  scattered  through- 
out his  informal  talk  illuminated  and  sent  home  all  the  points 
that  were  so  successfuly  made,  and  created  an  additional  in- 
terest as  only  personal  experiences  can. 

Aside  from  the  regular  meeting  was  held  the  annual  ban- 
quet of  the  Society  on  Friday  evening,  March  24,  1911,  at  the 
Great  Northern  Hotel.  The  dinner  was  an  entire  success,  and 
the  largest  crowd  the  Society  has  ever  had  at  such  an  affair 
was  out.  Prof.  Phillips  presided  as  master  of  toasts,  and  re- 
sponses were  given  by  Dean  Raymond,  Prof.  Wells,  and  Prof. 
Armstrong,  by  W.  A.  Kellner  of  the  Alumni,  and  by  Messrs. 
Jones,  Neufeld,  and  Ford  of  the  student  body. 

The  Society  has  enjoyed  the  most  prosperous  year  of  its 
existence,  and  is  now  the  most  active  engineering  society 
at  the  Institute.  This  is  due  to  the  interest  taken  in  the  Society 
by  the  students  themselves  and  by  the  civil  engineering  de- 
partment's faculty,  and  it  is  the  hope  and  wish  of  the  retiring 
officers  and  members  that  the  Society  may  be  even  more  nros- 
perous  in  the  future  than  it  has  been  in  the  past  year  of  1910 





Convincing  evidence  of  the  fact  that  the  professional  in- 
stinct has  been  instilled  in  the  minds  of  the  students  of  the 
Chemical  Engineering  course  is  shown  in  the  large  attendance 
and  interest  exhibited  at  all  the  meetings  of  the  society  this 

On  February  9th,  Prof.  McCormack  gave  a  very  interest- 
ing talk  on  the  subject,  "Testing  of  a  Municipal  Gas  Supply." 
Prof.  McCormack  is  particularly  well  qualified  to  speak  on 
this  subject,  as  he  was  one  of  those  to  figure  prominently  in 
the  drafting  of  the  new  city  gas  ordinance. 

Realizing  the  necessity  of  having  the  social  as  well  as  the 
technical  side  of  the  engineer  developed,  a  banquet  was  held 
on  February  24th  at  Kuntz-Remmler's,  with  thirty-one  mem- 
bers present. 

The  next  meeting  was  held  on  March  2d.  at  which  Prof. 
Mc Mullen  spoke  on  the  subject  of  "Cellulose."  He  told  of 
its  uses  in  explosives,  paper,  artificial  silk,  celluloid  and  other 
products  of  importance.  The  talk  was  followed  by  a  discus- 
sion on  the  structure  of  the  cellulose  molecule,  a  still  unsettled 
question,  and  some  original  conceptions  were  advanced  by 
Prof.  Freud. 

Quite  a  diversion  was  offered  on  the  evening  of  March 
15th,  in  the  way  of  an  illustrated  lecture  on  "The  Preparation 
and  Uses  of  Carbon."  The  talk  was  by  Mr.  Brainerd  Dyer 
of  the  research  laboratory  of  the  National  Carbon  Company. 
By  means  of  the  slides  we  were  enabled  to  follow  the  raw 
material  thru  the  plant  and  see  it  emerge  as  the  finished 
product.  Mr.  Dyer  had  with  him  a  large  number  of  samples 
showing  the  various  uses  to  which  carbon  can  be  put.  Among 
these  may  be  mentioned  electrodes  of  all  shapes  and  sizes,  tele- 
phone diaphragms,  rheostat  plates,  arc  lamp  carbons,  dry  cells, 
and  graphite  crucibles. 

Mr.  Young,  the  Chicago  manager  of  the  Hoskins  Electric 
Manufacturing  Co.,  has  invited  the  society  to  the  offices  of 
this  company,  where  he  will  demonstrate  the  practical  uses 
and  operation  of  electric  furnaces. 

The  final  banquet  of  the  year  will  be  held  on  May  12th. 
This  affair  is  held  primarily  for  the  reunion  of  the  alumni  and 
we  trust  that  the  attendance  will  even  exceed  the  unexpectedly 
large  attendance  of  last  year. 

H.    SIECK, 


204  THE   ARMOUR  ENGINEER  [May,  1911 


The  1911  meetings  of  the  Armour  Branch  of  the  A.  I. 
E.  E.  seem  to  have  surpassed  those  of  any  previous  year,  both 
in  the  interest  shown  in  its  papers  and  discussions  and  in 
average  attendance  at  meetings.  The  program  followed  has 
been,  as  usual,  to  have  papers  presented  by  members  of  the 
society,  by  graduate  engineers,  and  by  others  figuring  promi- 
nently in  the  electrical  world. 

The  society  was  addressed  on  January  26,  191 1,  by  Mr. 
T.  C.  Oenhe,  Jr.,  of  the  class  of  '08,  on  "Automatic  and  Semi- 
Automatic  Telephony."  The  data  for  this  paper  was  taken 
from  the  speaker's  nraetical  experience  in  this  line  of  engi- 
neering1 activity,  and  from  this  fact  he  was  able  to  bring  to 
the  notice  of  the  society  many  interesting  points  not  treated 
in  textbooks. 

On  February  16,  1911.  Mr.  G.  E.  Emmons,  of  the  class 
of  1911,  gave  a  talk  on  "Freaueney  Changer  Sub-Stations." 
The  data  for  this  talk  was  drawn  from  the  sub-station  of  The 
North  Shore  Electric  Company,  situated  at  Evanston,  111.  In 
dealing  with  the  subject,  Mr.  Emmons  dwelt  on  the  duties  of 
such  a  station,  and  in  addition  drew  out  the  complete  wiring 
diagram,  which  he  explained  in  detail.  During  the  discussion 
which  followed,  it  was  brought  out  that  these  sub-stations  are 
becoming  obsolete  in  the  neighborhood  of  Chicago,  due  to  the 
fact  that  both  25  and  60  cycles  per  second  are  being  generated 
by  the  large  companies,  and  then  transmitted  to  a  point  of 
distribution  at  high  voltage,  where  they  are  stepped  down  by 
means  of  transformer  stations. 

At  the  first  regular  meeting  of  March,  held  on  the  2d, 
Mr.  Erick  Fenger,  Testing  Engineer  of  the  Sanitary  District 
of  Chicago,  presented  a  paper  on  "Theory  and  Engineering 
in  Power  Plant  Testing."  Mr.  Fenger  outlined  briefly  the 
growth  in  the  importance  of  theory  in  power  plant  work  as 
installations  become  more  complex,  and  described  several  cases 
to  emphasize  this  point.  In  one  illustration  given,  he  showed 
by  actual  calculation  the  desirability  of  having  small  exciting 
currents  in  transformers.  Mr.  Fenger  also  gave  a  mathemat- 
ical proof  of  the  graphical  method  of  finding  the  regulation 
of  transformers,  a  method  which  is  quite  simple  but  not  ex- 
tensively used  in  this  country. 

Mr.  W.  W.  Drew,  of  the  class  of  1911,  addressed  the 
society  March  22,  1991,  on  "Commercial  Testing  of  Small  Mo- 

Vol.  Ill,  No.  2]  ENGINEERING  SOCIETIES  265 

tors,  and  the  Retardation  Method  of  Testing."  Facts  for 
the  first  portion  of  the  talk  were  taken  from  Mr.  Drew 's  expe- 
rience while  working  in  Milwaukee;  for  the  second  part,  from 
an  experiment  carried  out  hy  the  speaker  under  the  direction 
of  Mr.  Fenger. 

On  April  5th,  Professor  Barrows  read  a  paper  on  "New 
Types  of  Illuminants."  Introducing  the  subject  with  a  short 
history  of  the  development  of  illuminants  during  the  last  sixty 
years,  giving  the  date  of  the  first  incandescent  lamp  as  1878 
when  Swan  in  England  and  Edison  in  this  country  gave  to 
the  public  the  carbon-filament  lamp,  he  then  pointed  out  the 
rapid  strides  in  the  efficiency  of  lighting.  Prof.  Barrows  also 
gave  a  brief  review  of  the  most  important  types  of  gas  and 
electric  lamps  on  the  market  at  the  present  time. 

Meetings  are  scheduled  for  April  27th,  at  which  time  Mr. 
Tracy  W.  Simpson,  '09,  one  of  the  engineering  staff  of  the 
International  Harvester  Company,  will  speak  on  "Efficiency 

May  11th,  Mr.  Frank  F.  Fowler,  consulting  engineer,  will 
give  a  paper  on  "Engineering  Specifications." 

J.    H.    FLETCHER, 



The  Armour  Student  Branch  of  the  American  Society  of 
Mechanical  Engineers  has  also  enjoyed  a  most  successful 
year,  a  success  which  may  be  attributed  to  three  sources — the 
interest  taken  in  the  meetings  by  the  upper  class  men,  the 
help  and  many  valuable  suggestions  of  Professor  Gebhardt. 
and  the  attendance  of  the  faculty  members  of  the  mechanical 
engineering  department.  The  membership  has  not  been 
large,  yet  the  average  attendance  of  forty  has  exceeded  the 
number  of  enrolled  members  by  fifty  per  cent. 

On  February  1st.  1911,  Mr.  A.  II.  Anderson  delivered  an 
illustrated  lecture  on  "Railway  Draft  Gears."  A  good  part 
of  the  lecture  was  taken  up  with  a  description  of  the  theory 
of  the  shock-absorbing  parts  of  the  gear.  Several  curves 
were  shown  illustrating  clearly  the  manner  in  which  the 
shock  is  taken  up  and  converted  into  frictional  resistance. 

At  the  meeting  held  March  2nd.  Mr.  Paul  P.  Bird,  M.  E.. 
Chief  Smoke  Inspector  of  Chicago,  ^ave  a  lecture  on  "The 
Prevention  of  Smoke."       Mr.  Bird  during  his     talk     showed 

2m  THE  ARMOUR  ENGINEER  [May,  1911 

clearly  how  his  department  attacked  the  smoke  proposition  in 
and  around  Chicago.  One  of  the  very  interesting  points 
brought  out  during  the  evening  was  the  subdivision  of  the 
steam  power  plants  throughout  the  city  into  distinct  divisions, 
based  on  their  order  in  being  smoke  offenders  against  the 

Mr.  W.  Sieck,  on  April  12th,  gave  an  illustrated  lecture 
on  "Two  Cycle  Gas  Engines."  The  advancement  made  by 
the  two  cycle  engine  from  the  first  successful  type  down  to 
the  present  time  was  brought  out,  together  with  the  advant 
ages  and  disadvantages  of  this  type  of  prime  mover  over  the 
four  stroke  cycle  engine.  The  officers  for  the  coming  year  1911 
— 1912  were  elected  at  this  meeting,  the  object  in  so  doing  be- 
ing to  allow  them  to  become  better  acquainted  with  the  duties 
of  their  new  offices. 

May  10th  the  Society  will  hold  an  informal  dinner  and 
smoker  at  one  of  the  downtown  restaurants,  at  which  all  of  the 
members  of  Society  and  faculty  of  mechanical  engineering  de- 
partment will  attend. 

F.    H.    GRIFFITHS,